John Vladimir (Јован Владимир, ca. 990 – 22 May 1016) was ruler of Duklja, most important Serbian principiality. He was a just and peaceful ruler who married Bulgarian princess Theodora Kosara who fell in love with him when he was a prisoner to Bulgarians. He was later beheaded by Bulgarians and recognized as martyr. His relics are kept in Tirana, Albania, while the cross he held as he was beheaded is kept by a Montenegrin family and only shown in procession during the feast of Pentecost.