Matthew I Kantakouzenos

   Co-emperor with John V (q.v.) from 1353-1357; eldest son of John VI Kantakouzenos (q.v.). His career illustrates the internal strife that weakened the Byzantine state during the mid-14th century. Matthew emerged from the civil war of 1341-1347 with some territory to rule in Thrace (q.v.), which included Adrianople (q.v.). When John V besieged Adrianople in 1352, Matthew appealed to his father, who obtained help from Ottoman sultan Orhan (qq.v.). John VI then pressured John V to make Matthew co-emperor (1353). However, the following year John VI Kantakouzenos was forced to abdicate and Matthew's relations with John V turned into open warfare With his father gone, Matthew found his position weakened. In 1357 he was captured by the Serbs (q.v.) and turned over to John V, who forced him to renounce the title of co-emperor. After this Matthew went to the Morea (q.v.), which he ruled until 1380, despite John V's attempts to depose him.