The name Zagora comes from the Slavic term Zagore meaning "beyond the mountains". During the course of the 8th century, mainland Greece was subjected to numerous Bulgarian raids.
At the end of the century, a large scale Bulgarian military expedition headed by the chieftain Akamir was launched from Belasica. The Bulgarians plundered Thessaly, from their encampment which was located between modern day Volos and Velestino. The Byzantines called those Bulgarians Velegizitas or Vielesti. According to Kordatos, Volos, Velestino, Zagora and many other placenames in Magnesia originate from that period and are of Slavic origin. First mentions of the settlement under its current name come from the 13th century. In the 14th century Magnesia came under the control of Serbia, subsequent conquests by the Republic of Venice and the Catalans led to a big drop in the local population.