The hyperpyron remained the standard gold coin until gold coins ceased to be minted by the Byzantines in the mid-14th century. It too, however, was subject to gradual debasement: under the Empire of Nicaea (1204–1261), its gold content fell gradually to 18 carats, under Michael VIII Palaiologos (r. 1259–1282) to 15 and under his son and successor Andronikos II Palaiologos (r.