In the Middle Ages, men's underwear became looser fitting. The loincloth was replaced by loose, trouser-like clothing called Braies, which the wearer stepped into and then laced or tied around the waist and legs at about mid-calf. Wealthier men often wore chausses as well, which only covered the legs. By the Renaissance, the chausses became form-fitting like modern Hose, and the braies became shorter to accommodate longer styles of chausses. However, chausses and many braies designs were not intended to be covered up by other clothing, so they are not actually underwear in the strictest sense.

Braies were usually fitted with a flap in the front that buttoned or tied closed. This codpiece allowed men to urinate without having to remove the braies completely.HenryVIII of England began padding his own codpiece, which caused a spiraling trend of larger and larger codpieces that only ended by the end of the 16^th Century.

The modern men's shirt appeared during this era, but it was originally an undergarment. Renaissance noblemen also adopted the doublet, a vest-like garment tied together in the front and worn under other clothing.

The inventions of the spinning jenny machines and the cotton gin in the second half of the 18^th century made cotton fabrics widely available. This allowed factories to massproduce underwear, and for the first time, people began buying undergarments in stores rather than making them at home. The standard undergarment of the 19^th century for men, women, and children was the union suit, which provided coverage from the wrists to the ankles (this "second skin" style is more commonly known as long johnes today). The union suits of the era were usually made of knitted material and included a drop flap in the back to ease visits to the toilet.

1900s

By the early 20^th century, the mass-produced undergarment industry was booming, and competition forced producers to come up with all sorts of innovative and gimmicky designs to compete. The Hanes company emerged from this boom and quickly established itself as a top manufacturer of union suits. Textile technology continued to improve, and the time to make a single union suit dropped from days to minutes.

1910s

The increase in the number of underwear manufacturers necessitated the birth of undergarment advertising. The first underwear print advertisement in the United States ran in the Saturday Evening Posts in 1911 and featured oil paintings by J.C. Leyendecker of the "Kenosha Klosed Krotch". Early underwear advertisements placed emphasis on durability and comfort; fashion was never a selling point.

By the end of the 1910s, Chalmers Knitting Company split the union suit into upper and lower sections, effectively inventing the modern undershirt and drawers.

Meanwhile, the soldiers of World War I were issued button-front shorts as underwear. The buttons attached to a separate piece of cloth, or yoke, sewn to the front of the garment, and tightness of fit was adjusted by means of ties on the sides. This design proved so popular that it began to supplant the union suit in popularity by the end of the war. Garments of rayon also became widely available in the post-war period.

1920s

In the 1920s, manufacturers shifted emphasis from durability to comfort. Union suit ads raved about "patented" new designs that reduced the number of buttons and increased accessibility. Most of these experimental designs had to do with new ways to hold closed the crotch flap common on most union suits and drawers. A new woven cotton fabric called nainsook gained popularity in the 1920s for its durability. Retailers also began selling preshrunk undergarments.

1930s

Modern men's underwear was largely an invention of the 1930s. On January 19, 1935 Coppers inc sold the world's first briefs in Chicargo, illinois. The company placed a Y-shaped front and overlapping fly on knitted drawers in both short and long styles. They dubbed the design the “Jockey” since it offered a degree of support that had previously only been available from the Jockstrap (the company itself would later adopt the name Jockey, as well). Jockey briefs proved so popular that over 30,000 pairs were sold within three months of their introduction.

Meanwhile, other companies began selling buttonless drawers fitted with an elastic waistband, the first true boxer shorts (named for their resemblance to the shorts worn by professional fighters). Scovil manufacturing also introduced the snap fasteners at this time, which became a popular addition to various kinds of undergarments.

During World War II, elastic waistbands and metal snaps gave way once again to button fasteners due to rubber and metal shortages. Undergarments were harder to find, as well, since soldiers abroad had priority to get them.

At war's end, Jockey and Hanes remained the industry leader in the United States, but Cluett, Peabody and Company would make a name for itself when it introduced a preshrinking process called Sanfronization, which came to be licensed by most major manufacturers.

Meanwhile, some women readopted the corset once again, now called the waspie for the wasp-shaped waistline it gave the wearer. Many women began wearing the strapless bra, as well, which gained popularity for its ability to push the breasts up and enhance cleavage.

1950s and 1960s

In the 1950’s, underwear manufacturers began marketing printed and colored garments. What had once been a simple, white piece of clothing not to be shown in public suddenly became a fashion statement. The manufacturers also experimented with rayon and newer fabrics like dacron and nylon. By 1960, men's underwear was regularly printed in loud patterns or with images ranging from messages to cartoon characters.

Present day

Underwear as fashion matured in the 1970’s and 1980’s, and underwear advertisers forgot about comfort and durability, at least in advertising. Sex became the main selling point, bringing to fruition a trend that had been building since at least the flapper era (underwear is the last barrier before nudity, and thus it acts as a sort of gatekeeper to sex).

• Performers in the 1980’s such as Madonna and Cindi Lauper also got into the act, often wearing undergarments on top of other clothes.

Later, in the 1990’s, hip hop stars would popularize a similar style, known as the sag, which allowed loosely fitting blue jeans or shorts to droop low, exposing the underwear. In fact, in the case of Mark Whalberg, it was his success as underwear model for Calvin Klein (pioneering in sexy exposure of male flesh) that allowed him a double launch to showbiz fame as the first white hip hop star and as a respectable Hollywood hunk.

• Although it was worn for decades by exotic dancers, the Thong first gained popularity in South America, particularly in Brazil, in the 1980s. It was originally a style of swimsuit made so that the back of the suit is so thin that it disappears between the Buttocks. By the 1990s, the design had made its way to most of the Western World, and thong underwear became popular. Today, thong underwear is one of the fastest selling styles available among women and is even gaining some popularity among men.

• In the 1990s, retailers started selling boxer briefs, which take the longer shape of boxers but maintain the tightness of briefs. Though marketed as a new design, these are actually quite similar to the bottom half of the two-part union suits worn in the 1910s.