the history of the American T-shirt goes back to Wolrd War I when American troops noticed European soldiers wearing a comfortable,lightweight cotton undershirt during the hot and humid summer days.The European soldiers dealt with the heat by stripping off to their undershirts while the American soldiers stifled in their hot woolen uniforms.The undershirts guickly caught on with the American.The "T-shirt" got its name because of its simple design resembling the letter T.