THE LOINCLOTH - The first known underwear dates back almost 7000 years, when prehistoric man used leather to cover and protect his loins while running prehistoric errands. For several millennia, not much changed. Ancient Egyptian art shows everyone from the pharaohs on down the line decked out in loincloths of their own.
THE CODPIECE - Early codpieces were practical, having buttons on the front allowing for was access, but as hemlines rose, they started to take on a decorative function, too. When Henry VIII began to pad his codpiece in the 16th century, all of his loyal subjects followed suit. Codpiece padding and growth continued throughout the mid-sixteenth century before tailing off around 1590.
THE FLANNEL DRAWERS - From Victorian times into the 1930s, men had mostly worn tight-fitting knee-length flannel "drawers" beneath their pants and donned similarly snug flannel tops as undershirts. Not the most comfortable solution, but do not fear as the boxer short was just around the corner!
THE BOXER SHORT - in 1925 Jacob Golomb, the founder of the venerable boxing equipment company Everlast, started to tweak designs for the trunks worn by pugilists. Golomb realized that the leather-belted trunks fighters had been wearing weren't totally ideal, so he replaced the leather with more flexible elastic waistbands.
Boxer shorts weren't an immediate success as underwear, though. They lacked the support that drawers and union suits had offered, so men weren't crazy about them. It really wasn't until after World War II that boxer shorts took off to challenge their younger siblings, the briefs.
THE BRIEFS - In 1934 Arthur Kneibler, an executive and designer at the Wisconsin hosiery company Coopers, Inc., received a postcard from a friend who was visiting the French Riviera. On the front of the post card was a man donning a full torso bathing suit with. At this point Arthur had a light bulb moment.... what if the fitted swim wear design could be transformed into underwear? The Y-front was born.
THE BOXER BRIEF - Is a hybrid of the more fitted brief, with the longer leg of the boxer shorts hence the name Boxer Brief. This style first became popular in the 90s and continued to grow in popularity until modern times. It is believed around 60% of underwear sold in the UK is classed as a boxer brief style.
Our own Kensington range of boxer briefs were developed in collaboration with London based Jermyn St. tailors in order to create a modern fit suited to the needs of the man about town.
The above is with reference to mentalfloss.com