T-shirts began to be embellished with embroidery, lace, and frills in the 16th century, and men's outer garments—the doublet, or jacket—had a low neckline so that the shirt showed across the chest. By the end of that century, the shirt frill had developed into the ruff, which was a mark of the aristocracy.
The world's oldest preserved garment, discovered by Flinders Petrie, is a "highly sophisticated" linen shirt from a First Dynasty Egyptian tomb at Tarkan, dated to c. 3000 BC: "the shoulders and sleeves have been finely pleated to give form-fitting trimness while allowing the wearer room to move.
A T-shirt, or tee shirt, was originally worn only by men as an undershirt. Now it is defined as a short-sleeved, collarless undershirt or any outer shirt of a similar design. It got its name because it resembles the capital letter T in shape.