Degrees of Formality

I. Clothes of Official Power
     A. State
          1. Ceremonial Robes
          2. Court Dress
          3. Dress Uniforms
     B. Church
          1. Priestly Vestments
          2. Academic Regalia
          3. Legal Dress
II. Clothes of Celebration
     A. Evening

          1. Formal: White Tie
          2. Semi-Formal: Black Tie
          [3. Informal]
     B. Day

          1. Formal: Morning Dress
          2. Semi-Formal: Stroller
          [3. Informal] 
III. Clothes of Daily Life
     A. Professional
          1. Informal
          2. Smart Casual
          3. Business Casual
     B. Private
          1. Play & Exercise
          2. Yard Work
          3. Sleep

Introduction

Everything you choose to wear puts you somewhere on the ladder of formality.  It is crucial to understand formality as it is the factor that contributes most to social acceptability or awkwardness.  Dressing well can be done at any level of formality and for any occasion, posing no risk in comparison to its great rewards.  Dressing up to the right degree, however can be harder to get right for every occasion and poses greater risks, with the only benefit being that you do not stand out if your level of formality is correct.  

White Tie, Black Tie and Morning Dress

While you should always dress well without concern, you should be careful about how you dress up.  It is fine to be consistently acknowledged as dressing well, but there is no good reason to be recognized for dressing up or down.  If everyone else present at the occasion is equally dressed up, there is no reason for anyone to mention your level of formality.  If someone does, you have over- or underdressed.  Dressing up and calibrating your formality must be learned, however, because always being either under- or overdressed is a socially limiting course, while knowing how to be perfectly tuned to any occasion can open doors.  To dress appropriately for every occasion, you need to understand formality, where it comes from, and how it is created.  (My list of films and essay on the history of men's style as well as the books and links recommended below can help you with this.) 

There is a moral dimension to formality, as formality is what integrates you into the occasion and its population.  Ideally, how one dresses for an occasion should be less about one's individuality than about contributing to the occasion.  This more generous ethos used to dominate men's style.  For most of history, masculine style has been developed by the generationally powerful and rich and copied by the masses.  These style-setters knew how to have their own subtly unique styles while respecting custom and the solemnity of an occasion.  This is primarily because they were raised with an almost overwhelming respect for tradition.  After all, this tradition was the source of their and their ancestors' world of privilege.  Their security and luxury depended on the past, so tradition had an importance to them that is hard to overestimate.  Such men were still in charge of style at the beginning of the age of Hollywood when actors copied men like the Prince of Wales.

"Formal" dress literally moving from
boyhood (19 years old) to manhood (32 years old)

Since those first couple generations of stars have passed, celebrities have had less and less respect for the traditional principles that used to lead them - especially since the cultural revolution of the late 1960s.  Now many set their own standards as, for the first time in history, fashion is being led by a class of individuals from backgrounds that offer far less to thank tradition for than princes and lords have.  It is only once they become celebrities that they are thrust into wealth and prominence.  Their security and luxury depends on their own personal achievement in the present and ability to constantly market themselves as a reinvented commodity, so tradition is hardly that relevant to them.  The male formal dress broadcast into every home from red carpets today is one in large part independent of the forces of the tradition and propriety that had formed it for generations.  It is constantly subject to the whims of individualism.



Thus many celebrities do not approach formal events as social by nature nor see them primarily as opportunities for a group to come together to celebrate.  They seem to see red carpet events as just another venue to demonstrate their money-making individuality.  They may not believe they have tradition or each other to thank for their new world of privilege, but only themselves.  Thus, they may fail to see the evening as a social celebration within a world where tradition matters.  And perhaps given how young Hollywood is, how it is made up of almost all newly-made people, and how these people largely depend on their unique identity for their lifestyle, they are not so far off.

Speculating with less generosity, it may also be that these newly made men are in fact intimidated by dress codes and centuries of elite tradition they - and even their expensive stylists - do not understand.  This leads them into clownish originality in which they can hide their insecurity under the bravura of artistic individualism.  If one does not know how to conform, one can at least try to make a virtue out of nonconformity.

Number one? The number one blemish
on the happy couple's day, perhaps.

As celebrities are the current style-setters, this offers rather problematic guidance to everyone else.  It is unlikely that your income relies so much on your charismatic individuality or that you are invited to events because you offer desirable celebrity power.  When invited to an event like a wedding, you are most likely just being asked to come together with others to celebrate someone else's special occasion.  The event is really probably not about you.  At a wedding, the bride is the only person that should be making any conspicuous statement.  (As a general rule of thumb, you should not distract from the women at any event.)

If you choose to flout formality, you are only being a jerk.  Though you may think you are being clever, proving your individuality, or otherwise somehow showing superiority to those who do dress to standard expectations, you are actually behaving like a narcissistic juvenile.  You are drawing attention to yourself, making your presence a statement about how original you think you are.  Instead, you should be joining and contributing to a celebration that has required much thought and effort to put on.  You should add to the beauty of the occasion rather than clashing with it.

A gentleman, by which I mean a confident, capable, and generous man, sees something like a wedding as an opportunity to help make an occasion into an event for everyone attending and especially for those being celebrated who are really hoping for a memorable day.  He knows how to have his own style without making himself a center of attention.  Whether you are invited to a black tie dinner or a Superbowl party, someone has put work into creating that event.  An invitation obliges you to help your host create the ambiance they are envisioning.  Chances are you will spend far less time dressing than they will spend preparing the event, so embrace this easy way to contribute to a pleasantly memorable social experience.  Dressing is not just about you as long as you are around others.  It is about creating a pleasing and socially cohesive occasion.  Getting formality right, whether more formal or more casual, allows you to join in and contribute to an occasion and allows others to enjoy it.

Be a gentleman.  Learn and understand formality.

Generally, the more formal a look is, the longer men have been wearing it and also the more associated with wealth and power it is, which is a good part of the reason our culture's middle-class individualism is so uncomfortable with formality.  As the nation of the middle class, for Americans much of the spectrum of formality has become nearly obsolete.  The evolution of lifestyles at all class levels also makes it impossible for much of the traditional spectrum to fit logically into modern life the way it once did.  Above all, the most formal ensembles are also the oldest and, therefore, the next ones likely to lose relevance and disappear.  American men rarely need to worry about dressing beyond a suit, and very few even need to think about suits most of the time.

However, occasions do still arise in the States for some to wear ensembles more formal than a suit, making it helpful to understand these higher levels of formality.  More importantly for most men, even between t-shirts and suits there are a lot of fine gradients of formality, and calibrating your looks poorly can still do damage within your social spheres.  In our current world, we still have some ideas of appropriate formality, even if they work within a reduced range with less rigid rules.  Showing up to your job in a t-shirt and shorts on the one hand or in a suit and tie on the other while all of the other men are wearing polos and chinos is as much of a faux pas as serving as an escort at a cotillion in something other than White Tie.

I. Clothes of Official Power

At the top of the formality ladder are ensembles derived from the authority of the monarchy and the church.  If you have occasion and the right to wear any of these ensembles, you should know what they are.

 I.A. State Clothes

George IV and Edward VII

At the very top are ceremonial robes to be worn during events like the ceremonial crowning of a sovereign.  Here to the right are George IV and Edward VII in coronation robes.  There are many elements involved in what a monarch (not to mention everyone else involved) wears on the day of a coronation.  There are other, similar ensembles worn by royals and peers on other occasions.  One will never, of course, see any of them in the U.S.  They are purely aristocratic.

Pre- and Post-Revolution Court Dress

Another level of formality that survived from the ancien régime is Court Dress, a dress code required for various functions related to a royal court.  It is the code that has longest held on to breeches, the knee-length hose abandoned in favor of long pants, or trousers, after the Revolution (see this essay on the history of menswear, if you have not yet).  Just like coronation robes and other ceremonial aristocratic clothing, Court Dress is of no concern to any American man living and functioning within the U.S.

The American military is patterned after the British military, which itself was formed over many centuries of the monarch calling upon local warlords able to raise forces for war.  Over time they were given increasingly institutionalized status and privileges from the monarch which elevated them into the developing system of the peerage with its many titles.

All of this required ceremony, of course, and for centuries, military uniforms were as symbolic and ceremonial as they were practical, if not more so.  It was not until late in the 19th century that it was decided that British soldiers should be dressed in a way that calls as little attention to itself as possible (thus the rise of khaki). Today those serving in the American military have Dress Uniforms worn for ceremonial occasions, which indirectly symbolize authority once granted by monarchs.

I.B. Church Clothes

Kings and queens have not been the only representatives of ruling power on earth, of course.  The church had massive power over every individual in England and the continent for many, many centuries.  Priests from local authorities up to the Pope wear clothing symbolic of the consecration of their lives to the church and the authority given to them by it.  Priest's Vestments are still worn and, like military dress uniforms, can be seen today in the U.S.  Some are worn only for special occasions, others routinely.

In the later middle ages, schools run by the church to train clergy developed into the universities of Europe.  Thus, even though they were not clergy themselves, later scholars continued to wear robes similar to those worn by the priesthood even after many schools were founded by secular authorities.  While almost no educational institutions in the U.S. still require teachers or students to wear Academic Robes in class, examinations, or to dining halls, almost all of them still call for robes at the end of the year at commencement exercises.  As the majority of American men do graduate from high school, and as most high school graduations do feature robes, this is the highest form of dress most American men get to rightfully wear, even if often with discomfort and ironic disfiguration.

The four faculties of the medieval university were theology, law, medicine and arts.  Today parts of the legal profession still wear a version of the academic costume as a professional uniform.  In the United States, this has been reduced down to just robes worn by judges, though a more robust system of Legal Dress continues in the U.K. and elsewhere.

Though aristocracy was not institutionally transplanted in America, the military, church, university, and law were along with their forms of official dress.

II. Clothes of Celebration

Before I discuss White Tie and Black Tie, it is important to fully grasp that though they are now generally clothes for celebration - if not ceremonial celebration, for generations these were ensembles worn every day after sundown by the leisure classes as regular evening wear.  They were not ceremonial but daily clothes (working your way through my list of films will give you a solid feel for this). The fact that no American men have a routine that requires formal evening wear for daily dress is one of the reasons it is losing its place in our dress vocabulary.  Now it is restricted to celebratory use, and American men are far more likely to wear Academic Robes or Dress Uniforms than White Tie in their lifetimes.

II.A. Evening Formal Clothes

Brummell and Astaire in Full Dress

Aristocrats dressed for the evening before the French Revolution.  After the revolution, though the rich and titled moved towards Beau Brummell's simpler and less aristocratic look, they continued to change their clothes multiple times a day, matching every ensemble to occasion.  Dinner and other evening gatherings were held by candlelight and were intentionally beautiful affairs for the leisure classes.  Women wore their most elegant gowns while men dressed in darker, more subdued tones than they had before the revolution.  To serve as a backdrop distracting from the women as little as possible this dress developed, through the course of the 19th century, into a visually simple ensemble of black and white today called White Tie, full dress or a dress suit.

By late in the century it was a very strictly controlled look worn at any evening gathering with women present, from dinner at home with just the family to balls, evening performances, and any other society gatherings. Until the ascent of the dinner jacket, it was also worn in the evening by men at their clubs.  For a detailed discussion of the history and elements of this ensemble, visit this page describing White Tie. Today few men in the U.S. are familiar with White Tie and even fewer will ever have occasion to wear it, as it has gone from daily to celebratory evening dress and then to extremely formal and rare.

Cary Grant and Sean Connery in Dinner Jackets

In the later 19th century, the Prince of Wales and future Edward VII popularized wearing a "dinner jacket," a coat that lacked the tails of a full dress coat, featuring instead the skirt of a sack coat (a sack coat is the cut of suit and sports coats).  It was not until the 1920s that the dinner jacket, or Black Tie, began to appear regularly in mixed company or at more formal dinners.

Until that time it was evening wear for men among men or sometimes for men at home among family and was considered rather casual as, firstly, it was a sack coat, the most recently developed and most casual kind and, secondly, it probably descended from the smoking jackets men sometimes donned apart from the women after dinner to have a smoke.  World War I did much to speed up the dissolution of the power and traditions of the aristocracy and give the leveling forces of democracy greater sway.  Thus, from the 1920s on Black Tie, being more casual, continually eclipsed White Tie in the evening.  World War II once again hastened the decline of elite traditions while promoting a leveling culture driven from the bottom up.  In the second half of the 20th century, the idea of dressing daily for the evening crawled to its death as even Black Tie became used more for celebrations than for daily evening clothes.

American men are much more familiar with Black Tie than White Tie, usually calling it a "tuxedo" (after the country club where it was first introduced in the States in the 1880s).  Very few, however, probably consider it a casual version of daily evening wear.  Today many men know Black Tie primarily from its often-compromised versions on the red carpet of televised events which are, originally were, or imitate those that were evening dinner parties with awards. Most American men's personal experiences with Black Tie are ill-fitted, rented, polyester affairs like high school dances and weddings, where the tie is likely to be other than black.  In so many of these cases it no longer makes sense to refer to the ensembles worn as "Black Tie" or even as "dinner jackets."  "Tuxedo" is probably more appropriate, as it is better suited to indicate everything from powder blue ruffled shirts and bell bottoms to a matching set of metallic or neon [long] tie, vest, and pocket square that likely contrasts with the neon or metallic coat and trousers.

Most men will also likely at most wear Informal (a simple suit - see below), if that, for most evening celebratory events considered formal.  Where it lives on, traditional Black Tie, just like White Tie, is a black and white ensemble meant to serve as a simple, muted backdrop to the more colorful and interesting evening wear of women - a traditional gesture of chivalrous restraint.  For a detailed discussion of the history and elements of the classical ensemble, visit this page describing Black Tie.

II.B. Day Formal Clothes

George VI and his great-grandson Harry in Morning Dress

This is a concept almost extinct in America, though it persists across the Atlantic where it can be seen at various formal daylight events.  It is the traditional dress for weddings in the day or afternoon, though most American weddings today would look a bit overdone with the men in formal day clothes, or Morning Dress.  It descends from what men of the upper classes often wore during the day, when its cutaway coat was a semi-formal alternative to a frock coat.

In its final and extremely rare American manifestations, it is worn ceremonially, as most ensembles are at the end of their life-cycles.  Reagan, the last style-conscious president, wore Morning Dress in one of its last official political appearances when meeting Emperor Hirohito in the early 1980s.  If you watched the video offered above for Academic Robes, you saw some Morning Dress still worn at Harvard commencements.  In a day when most American men feel put upon to wear a suit, the cutaway morning coat is as foreign and threatening as an evening tail coat. Our middle-class ethos is unlikely to let many feel comfortable in such an extravagant luxury as a coat with tails.  For a discussion of the elements of this ensemble, visit this page describing morning dress.

The Stroller on a young JFK and an inaugurated Reagan

If you live in a social world where Morning Dress makes sense at a wedding, you probably do not need the advice of a Poor Man's Jeeves.  Most American men are not at home at such rarefied sartorial heights and when attending a formal daytime event should probably put together a conservative but elegant version of Informal (or even just Smart Casual - see below) appropriate to season and setting.

If you do feel like bringing a bit more tradition to a daylight event, a Stroller (Black Lounge in the U.K.) might be a great solution.  It is basically Morning Dress with a sack coat instead of a cutaway.  Those unaware of the history of men's style should accept it quite easily, as the combination of dark jacket and trousers with a waistcoat and long tie is not far off from what many wear as a "tux" at proms and for weddings.  Those with a sense of history will appreciate that it is correct daytime [semi-]formal.  Strollers are also discussed at the link on Morning Dress.

Daylight Dress Uniforms should certainly be considered by men with a right to them.  Black and White Tie are still only considered appropriate by those who know for evenings despite widespread, daylight abuse. 


III. Clothes of Daily Life

III.A. Professional Clothes

Brooks Brothers' No. 1 Sack Suits and an Informal Duke

Now we have descended to the level of formality with which most American men are rather familiar if only occasionally comfortable.  Once one considers all of the levels of formality above the professional tier, and once one understands how the leisure classes used to dress day and evening, every day, one can understand how a suit could end up with the designation "Informal."  As most of the aristocratic traditions of dressing for occasion have atrophied in the States, for most Americans today, a suit and tie is the peak of formality (except for rented "tuxes" and graduation robes), and only a small percentage regularly wear one.  Still, there are many living in the States today for whom a suit is the normal, daily dress for themselves and the other men they see every day.

A suit consists of a sack coat and trousers of the same cloth (weave, pattern, color, etc.).  It originally and then for a long time featured a matching waistcoat as well, though by mid-20th century most suits were worn without them.  Though it would become the uniform of middle-class businessmen, if not the symbol of capitalism itself, this ensemble was developed in the mid-19th century as rather casual daytime dress by the leisure classes.  They called it a "lounge suit," as their normal daylight dress was a frock or morning coat, and they only wore suits to lounge around their own houses.  One would have to change into something more acceptable when leaving the house to make social calls or to go into town.  By the turn of the century, however, it had become an acceptable business uniform and was widely worn socially, especially in the States, though the frock and cutaway were still expected for more formal occasions.

Smart Casual with a Tie

Before we descend below suits, a word of caution about the use of the terms "Smart Casual" and especially "Business Casual."  Many workplaces only use the latter term, and when considering all of the ways "Business Casual" is used across professions and regions right now, it ends up covering a range including every ensemble below a suit that features a collar and long pants.  Some describe it as a sports coat, slacks, and tie.  Others describe it as jeans or chinos with a polo.  Obviously, if you followed one of these descriptions and went to work at a place that used the other, you would be inappropriately dressed.

What you need to do for the workplace is to determine, regardless what the dress code is called, what everyone is actually wearing.  You should always dress basically the same (in terms of types of garments) as all of your pay-level peers but much sharper (fit, combinations, quality, etc.).  The way I delineate "Smart Casual" and "Business Casual" here is based on what seems to me to be their most logical and consistent usage, but you must be careful not to assume that you ever know exactly what someone means when they say "Business Casual" and should be guided by what is actually worn in a specific workplace.

Smart Casual sans Tie

So now, let us take another step down to what I and many others call Smart Casual, which I delineate as an ensemble featuring an odd coat (one that does not have matching trousers).  It descends from English country and sports clothing of the early 20th century, a fact reflected in its dependence on the "sports" coat.  As it was originally a very casual, youthful, and colorful code, Smart Casual allows for considerable pattern and color coordinating and is typically acceptable being louder than Informal.  It may or may not include a tie.  Generally, the trousers are wool rather than cotton.  In fact, I would consider an ensemble with wool slacks, a dress shirt, tie and nice sweater Smart Casual, even though it lacks a jacket.  A jacket worn with nice jeans, a dress or sports shirt, and no tie would also qualify as Smart Casual for me.  Smart Casual has a variety of possibilities.

Where statesmen, businessmen and lawyers typically wear Informal, well-dressed creative types such as writers, artists and scholars might wear Smart Casual professionally.  They generally have the autonomy and respect in their positions to freely choose from many options, unlike men who wear Informal above them or Business Casual below them and are more bound in their choices by hierarchy.  Some men who generally wear suits to work may opt for Smart Casual off the clock.

Business Casual

At the bottom of the professional clothing range is Business Casual.  It is mostly derived from the sports and weekend clothes of American men at mid-century.  At most workplaces, this simply means pants with a belt and a collared shirt tucked into those pants.  Perhaps this definition is sufficient, though it leads many men into looks that are rather sloppy and without any real power.  In comparison to Smart Casual, there is much more cotton than wool in Business Casual, the trousers usually being chinos, cords or jeans, though the formality-confused combination of wool trousers and pressed dress shirt sans coat and tie is surprisingly widespread and also often called "Business Casual."  Business Casual is less likely to feature dress shirts, with polos and sports shirts being more common.  At the top of Business Casual, one may wear a tie and perhaps even pair it with a sweater, though a tie with layers puts an ensemble on the borderline between Business and Smart Casual.

Business Casual is the norm for most men who have any kind of dress expectations at work in the States that are not either a uniform or Informal.  Just because one works within a dress code of Business Casual does not mean one cannot do it quite well and look sharp.  See the following link for dressing your best in business casual.

All of these images for Smart and Business Casual are taken from the "What Are You Wearing Right Now" threads on Style Forum (linked below), where you can learn a lot - and read a lot of ego-fueled stupidity - about how to dress from real men.

III.B. Private Clothes

The clothing here at the bottom of the formality ladder needs little explanation.  You should be familiar with pajamas, bathrobes, shorts, t-shirts, sweatshirts, and exercise clothes.  If you want your clothes to project more power, then these kinds of clothes need to be worn only when necessary: for sleep, labor, sports and play.  Ironically, almost everything worn up to and including formal evening dress was once a form of sports clothing.  Yesterday's sporting clothes continually become today's formalwear.

Regardless, if you want to express more power with your clothes, items that are worn for sports today - synthetic shorts and t-shirts, etc. - should only be worn for actual exercise or play.  Perhaps your [grand]son will wear them to church or even get married in them, but for now they are still only clothes for exercise or play.  Any other time you are seen by anyone, family or otherwise, and you are not engaged in sports or play, working in your yard, or going to bed, you should at least be wearing Business Casual.  Also, even when wearing Private clothes, it should be done well just as at any other level of formality.  What you wear when not "dressed up" can project as strong an impression of your power and aplomb as what you wear when more formality is expected.



Review of the Coats by Cut

From casual to formal clothes, one important factor determining formality is the cut of the coat worn.  To help you keep everything mentally organized, it may help to see and understand all of the different kinds of coats next to each other.  Below is a set of images from the Edwardian era (well, strictly speaking, some years after Edward's death), when all of these distinctions were still very important and all of these different types of coats very much in the better-dressed man's regular rotation.  (For a fantastic demonstration of where men's style was at this time - and of how to study style history by means of films - read this article and view the movie it describes.)  Below the pictures of the Edwardian state of the four coats, each coat is discussed further.

(click to enlarge)

The most formal coat worn daily in the early 20th century was the tail or dress coat (White Tie), which dated back to Brummell's time - the Regency era.  It was, in the early-19th century, the cut of both day and evening coats, before being confined to evenings by mid-century.  Produced by both the desire for comfort in riding as well as the late-18th century obsession with the masculine perfection classical Greek statues were assumed to embody, the dress coat was an innovation revolutionizing the appearance of its wearers.  It was created by removing the front of a coat's skirt, which had been quite long.  The bottom of the accompanying waistcoat was raised all the way up beneath the coat's front hem.  This entirely exposed the front view of a man's upper legs and his hips, an area previously well-covered.

(click to see The Rise and Fall of White Tie)

Before this, men's calves dressed in silk stockings had been a focal point for expressing masculinity.  The display of virility here was so important that those stockings had frequently featured padding for those with more modest calves.  This habit of padding was continued by those who needed it with the tight, long pants first worn with dress coats.  Tail coats did not do away with the display of muscular legs but dramatically extended it up beyond the knee to the waist.  Now the entire lower body was exhibited presenting a man as Praxiteles' Hermes or the Apollo Belvedere.

This original aesthetic intent is entirely lost on some of White Tie's few privileged wearers today who, terrified of a high waist, wear White Tie with their pants hanging off of their hips along with farcically long waistcoats that stick out underneath the bottom of their coats (as they never should).  This shortens and deforms the men's legs, gives unflattering emphasis to their bellies, and thereby compromises the aesthetic logic of the ensemble, destroying its antique proportions and classical appeal.  It is unlikely these men and their stylists know that an invitation to wear White Tie is an opportunity to enjoy a tradition of presenting oneself as a Greek god.

Padded underwear becomes much less important once
a Victorian man is cocooned in a frock coat

A day semi-formal alternative that soon became popular alongside the dress coat was the frock coat, which came down to about the knee all the way around, closing off the display opened up by the dress coat.  By the middle of the 19th century, the Early Victorian era, the dress coat was worn only for evening, and the frock coat had become the formal day option.  It provided much more modesty in the day.  Some of the modesty of the day's frock coat also seeped into evening wear.  Though evening dress still featured the tail coat that exposed a man's lower half, evening breeches (pre-revolution pants that come just to under the knee) were replaced as the century progressed with long, looser pants, just as long pants had replaced day breeches around 1800.  The frock coat typified an age of reduced masculine display.

Also around the mid-19th century, the cutaway or morning coat (Morning Dress) became the day semi-formal alternative to the frock coat.  Despite the other trends towards less display, morning coats held on to a bit of the classical sexuality that the daylight dress coat used to provide.  Though it completely covers the hips, as a variety of tail coat it still exposes some of the thigh.  For the short time that he was king, Edward VIII helped attenuate some of the prudery from his great-grandmother Victoria's time by replacing the frock coat with the morning coat at court.  Still, such aristocratic display was not in harmony with the middle-class morality of the late-19th and early-20th centuries and was not to remain acceptable forever in the tastes of the masses.

The sack coat (Black Tie, Stroller, Informal, and Smart Casual), also began to be worn, albeit rarely and primarily in private, in the mid-19th century.  It was invented at this time as a short, boxy jacket - much like a sack with sleeves - and was extremely casual.  The sack coat was soon paired with matching trousers, or trousers that "followed" the coat ("suit" comes from the Old French for "following").  The ensemble was called a "sack suit" for obvious reasons and a "lounge suit" because it was so informal - the sports shirt and jeans, or perhaps even t-shirt and shorts, of the Victorian era.  As middle-class morality continued to grow in dominance until it extinguished interest in the choices and values of the leisure classes, the more modest, pedestrian sack coat with its simple, easily mass-produced shape continually took the ground held by all of the other coats.

James Bond in Formal, Informal, and Casual Sack Coats

Despite the sack coat's rapid ascension propelled by the explosive growth of the middle class, of the four types of coats, the frock coat is the only to have disappeared entirely.  It went irretrievably out of style by the 1930s, at which point the morning coat became the peak of daytime formal, and the Stroller took the morning coat's place as semi-formal.

By the early 20th century the sack suit had become acceptable for business.  The evening sack coat, or dinner jacket, had come into its own as semi-formal, rather than casual, evening wear.  The sack coat had also already been worn for sports and spectatorship as a sports coat and blazer, which were moving into contexts beyond sports.  The 1920s to the 1960s was really the age of the sack coat, with older cuts only called upon for very formal if not, especially as time passed, ceremonial occasions.

Since the 60s, even the lowly sack coat has taken on more and more of a ceremonial role as the other coats have all but disappeared.  In fact, quite a few men today feel that putting on any shirt that features a placket, buttons, and collar (i.e., not a t-shirt) and tucking it in is already sufficiently formal, if not a daring act of panache deserving praise.  Many men see no reason or occasion to ever wear any kind of coat other than for, perhaps if their bride absolutely insists, their own wedding.  There is no shortage of funerals, weddings, and church services with many men in just their shirt sleeves.  The middle-class need to cover up that displaced the dress and morning coat has itself given way to a middle-class distaste for layers in general and the traditions of higher classes they connote.

Conclusion

Unless you are related to the Duke of Cambridge,
you probably will not wear it all

You likely will never dress in terms of this full range of traditional formality and may never don any coat other than a sack coat - and even that infrequently.  What is most important for you to do is to think through the full range of occasions in your real life (work, parties, sporting events, weddings, etc.), and think of what the actual people there will really wear (not what sources like this site say they should wear).  Think of what most men there will really wear and consider also what the most casual and most formal outfits will be.  Think this through for each type of occasion in your life to identify the range of formality for each occasion.  Figure out how to dress your best within each range you identity.  For a discussion of the nuances of formality in the Professional degree of formality, click here. 

The wardrobe you build should allow you to dress extremely well with appropriate formality for every occasion that occurs in your own life.  As you examine all of the resources offered here and consider the images and discussion they provide, keep identifying what will work within the occasions of your life.