Plovdiv city was possibly at times a vassal of Bulgaria or Venice. Ivan Asen II conquered the duchy finally in 1230 but the city had possibly been conquered earlier. Afterwards, Plovdiv was conquered by Byzantium. According to some information, by 1300 Plovdiv was a possession of Theodore Svetoslav of Bulgaria. It was conquered from Byzantium by George Terter II of Bulgaria in 1322. Andronikos III Palaiologos unsuccessfully besieged the city, but a treaty restored Byzantine rule once again in 1323. In 1344 the city and eight other cities were surrendered to Bulgaria by the regency for John V Palaiologos as the
Plovdiv the Slavic name began to appear as "Papaldiv/n Plo(v)div, Pladiv, Pladin, Plapdiv, Plovdin", which evolved from a Thracian variant "Pulpudeva". As a result, the name has lost any meaning. In British English the Bulgarian variant "Plòvdiv" has become prevalent after World War I. The Crusaders mentioned the city as "Prineople", "Sinople" and "Phinepople". The Ottomans called the city "Filibe", a corruption of "Philip", in a document from 1448. Plovdiv is located on the banks of the Maritsa river, southeast of the Bulgarian capital Sofia. The city is in the southern part of the "Plain of Plovdiv", an alluvial plain that