During the earliest civilization, people wore animal skins to shield themselves from the environment. Though wool was the most common of these clothing. Even to this day there fashion in clothing is sketched on pottery. Also the textiles that are made are usually use to trade or for the king. The early Sumerians men usually wore waist strings or loincloths (which provided little protection,) later skirts was introduced that hung over the knees. For the women worn a shawl that warped around their bodies. They would have decorative patterns sometimes. In the later years they would have worn sown outfits.
Sources: http://www.ancientgreece.com/s/Clothing/
http://www.palmbeach.k12.fl.us/eagleslandingms/MesopotamiaClothing.pdf