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
History of Plovdiv and the Day of Plovdiv. After Unification Plovdiv remained the second city in population and significance after the capital Sofia. The first railway in the city was built in 1874 and after 1888 it was linked with Sofia. In 1892 Plovdiv became host of the First Bulgarian Fair with international participation which was succeeded by the International Fair Plovdiv. After the liberation the first brewery was inaugurated in the city. In the beginning of the 20th century Plovdiv grew as a significant industrial and commercial center with well-developed light and food industry. German, French and Belgian capital was invested in