The first documentary notice about Sebes, "Terra Sebus", dates from 1224. In 1245, Pope Inocentiu the IV-th   issues an act that empowers the priest Teodosie of Mallembach (Sebes) to raise funds from some  parishes  for the reconstruction of the city devastated by the great Tatar invasion in the years 1241-1242.

The name of Sebes ( Sebis =quick), used for the first time in the early Middle Ages, comes from the river that crosses the mountain town. Because the locals were using the hydraulic force of the river,  the Saxon colonists in Transylvania, that came in the second half of the twelfth century, gave the city the name of Mühlbach (the mills river).

 As in other urban settlements in Transylvania, Sebes city was founded by German colonists, brought by the Hungarian Royalty from the need to consolidate the Arpadieni dynasty , to guard the southern borders of the empire. In 1301, the town appears in documents as "Sebus" and in 1341 it is mentioned "Civitas Sebus.