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 Airport and a tie-up between Hainan and Plovdiv Airport Invest. On 28 March 2018, Bulgarian Government awarded the consortium of HNA Group and Plovdiv Airport Invest a 35-year-long concession on Plovdiv airport in return for investments reaching €79 million, including a new cargo and passenger terminal. On 19 of July the consortium of HNA Group and Plovdiv Airport Invest have declared that it won't sign the concession contract which opens the road for the classified on the second place to take the concession. On the west side of the airport is located 24th Helicopter Air Base of the Bulgarian Air Force,