I noticed that there was a celebration or commiseration of the 150th anniversary of the suit recently. Well the suit did not spring full-formed from a designer’s brow a century and a half ago but was a slow evolution throughout time. In the very earliest ages of humankind people wore animal skins but learned how to weave fabric from plants and animal fur or hair.
Patterning and stitching developed along the way. As you can imagine the stitch would have been pretty basic and every piece of fabric taken off the loom would have been stitched together to form a body piece and sleeves.
There were no factories and every piece had to be made from the ground up so nothing was wasted. The earliest form of sewing and patterning was called rectangular construction because it was taking all of the rectangle from the loom and using it. Men and women wore tunics. You might call them dresses today or giant T-shirts, as the T-shirt is an evolved form of rectangular construction because the sleeves are formed where they join (in some cases). Since humanity began in Africa and spread out from there the Middle East and Africa held the first developed civilizations.
By the time rectangular construction was perfected humans had been dressing themselves for thousands of years. It’s hard to say exactly when this actually started because fabric tends to rot away. Only the earliest images on stone give us an idea of what the Egyptians, Babylonians and Sumerians were wearing.
For outer wear in the colder climes people wore mantles, a rectangle of wool or fur or other heavy warm fabric. This eventually evolved into the cape, a shaped half circle or full circle cloak. However, at the same time the cultures that spent a lot of time in snow or on the steppes did develop coats. The Norse had coats and pants such as the 4th century Thorsberg coat depicted to the right. The button, as a fastening came along around the 13th century. Before that, lacing, and pins of elaborate construction were used for closings.
But these were all coats, whether Norse, Persian or Mongolian. Cutting and patterning techniques became very elaborate; weaves as well continued to become refined. There is debate that we’ve lost some of the techniques shown in paintings of the Middle Ages, such as veils so thin that they were nearly invisible. Out of the Elizabethan era of the 1600s men were wearing doublets. On colder days, capes were thrown over these. By the Baroque and Rococo periods (which refers to art more than fashion) of the late 1600s to early 1700s elaborate doublets and coats of brocade were common. Overcoats became common as the swords slimmed down to the rapier blade, and muskets came to the fore. This is probably the true beginning of the suit, a doublet with a matching coat that is longer over top.
Slowly over the next hundred years this turned into the coat and tails with a vest beneath the coat. Although the era of Louis XIV brought the froofroo lace and brocade to a height, and ostentation was part of the game, warmth also played a part. The ostentation carried over so that class was always shown by the cut of the cloth, the expense of the material and the dyes, and the ornamentation. As the more staid Regency and Victorian eras came around men (who once had been brighter peacocks than women in fashion) still needed to show their status. The more layers to your suit, the more high up you were.
Thus was modern the suit born. So, in the essence of the modern suit consisting of jacket and matching pants, and perhaps a vest, this did begin in the 1800s but as you can see it was a long evolution from a garment worn for warmth to one of nearly pure status. Status to depict class or responsibility or competence. Lawyers rarely wear T-shirts and cowboy boots in the courtroom or to meet clients. This description here is a gloss of the history of the suit but it gives you an idea of how fashion changes. Other influences can be political, economic or geographic. But in the end, it is what humans consider fashionable that makes the trend.