Stephen III
In 7 March 1471, Radu fought the Battle of Soci against Stephen III, his future son-in-law, for possession of Chilia (now Kiliya in Ukraine). Slavo-Romanian chronicles relate that Stephen III had a "war with Radu voivode for Soci". Stephen III's relationships with Radu were hostile. He invaded Wallachia on several occasions during Radu's reign, dethroning him four times in response to Radu's vassalage.