History of Men's suits

The suit is the traditional form of male formal attire in the Western world. The modern suit did not appear until the early-to-mid nineteenth century, but the origins of its coat can be traced back to the revolution in men's dress set by Charles II, king of Great Britain in the 1660s. A particular style of this was adapted and popularized by British dandy Beau Brummell by the early 1800s.
In the 1660s, restored English king Charles, following the example of the court of Louis XIV at Versailles decreed in 1666 that at court, men were to wear a long coat or jacket, a waistcoat (originally called a petticoat, a term which later became applied solely to women's dress), a cravat (ancestor of the modern necktie), a wig, and breeches or trousers gathered at the knee, as well as a hat for outdoor wear.
By the early 1800s, Britisher Brummel's style trend led men in Europe to wear understated, beautifully cut, perfectly tailored versions, adorned with elaborately knotted neckwear. Brummell's stylistic influence is credited with introducing and bringing to fashion the move for a pared-down modern man's suit worn with necktie. He additionally popularized regular bathing for males which went with his versions of the suit. (Johnson, Birth of the Modern)
Coats with matching trousers or even waistcoat have gone in and out of fashion over the last four centuries however the modern lounge suit coat is still derived from historical coats. Although it is hard to see the outline of the modern business suit coat in the elaborate and brightly-coloured court dress of the seventeenth century, the basic pattern has survived for more than four hundred years with some adjustments, despite the abandonment of wigs and knee breeches after the French Revolution, the rise of British tailoring, which used steam, pressure, padding, and stiffening to mould woolen fabric to the body, the invention of the modern necktie in the late nineteenth century, and the gradual disappearance of waistcoats and hats during the last fifty years.
What we call the modern suit was originally a nineteenth-century English innovation in dress. Originally the term usually referred to a lounge suit and was worn only in the country and at the seaside. At that time morning dress and frock coats were not part of a 'suit' because they were usually worn with non-matching striped trousers, and having matching waistcoat and trousers was originally considered more informal. The term "ditto suit" was also transiently used due to the matching waistcoat and trousers, these sometimes having coats more resembling a frock coat or a morning coat. The "sack suit" is a North America derivative of the English lounge suit which looked even looser and more casual because it lacked darts. In the nineteenth century, for more informal occasions, men still wore morning dress as a more casual alternative to the formal frock coats then considered appropriate business and day time formalwear. The lounge suit was thus an even more casual form of dress and was reserved solely for recreation activities.
The lounge suit became increasingly popular through the later nineteenth century as casual town daywear until it started to become an acceptable alternative to the morning coat as town wear in the early twentieth century. As the lounge suit became increasingly popular, even the humblest men would have at least one suit to wear on Sunday to church as part of their "Sunday best." Victorian men who were able to afford it would still wear a frock coat to church. Prior to 1935 (and again for a short time in the 1970's) men preferred their jackets and waistcoats to be fitted snugly. The trend since 1935 has been for loose fitting jackets. The waistcoat or vest was worn regularly with the suit until World War II when it fell out of fashion due to the loose style then in fashion. The waistcoast returned to fashion when the fitted style became prevalent once again in the the 1970's. This style quickly became associated with disco music and culture. Movies like Saturday Night Fever helped popularise the waistcoat as a fashionable piece of dresswear. The three-piece suit quickly became associated with the disco culture. The backlash against disco quickly led to the demise of the popularity of three piece suits which were criticized as being "effeminate" by men such as Steve Dahl who disapproved of disco and organized a campaign to get rid of anything associated with it. By 1983, the wearing of waistcoats had become a rare sight. This is exacerbated by the fact that men prefer loose fitting coats. A waistcoat that is not fitted properly will rise when one sits down and will quickly become uncomfortable.
At the end of the nineteenth century, an informal evening version of the lounge suit emerged in England, known as a dinner jacket in British English, in a dress code referred to as black tie. When it was imported to the United States, it became known as as the tuxedo or the penguin. The dinner jacket was originally called a 'dress lounge' in England to indicate that it was a lounge suit for evening wear. The 'dress lounge' was originally worn only for small private gatherings and white tail tie was worn for large formal events. The 'dress lounge' slowly became more popular for larger events as an alternative to full evening dress in white tie. As black tie grew in popularity, it has became increasingly acceptable as formalwear and today has all but replaced white tie, which today is only seen at ultra-formal occasions. The daytime formal equivalent to white tie is morning dress, but in the United States this too has become uncommon and the daytime semi-formal dress called the stroller is more common. The stroller is itself a form of 'dress lounge' - a day time semi-formal lounge suit version of morning dress.