As told by the Bychowiec Chronicle, Voivode of Vilnius Petras Goštautas married a Polish lady from the House of Buczacki and converted to Catholicism [REF].
The story was repeated by Maciej Stryjkowski (1547-1593), Albert Wijuk Kojałowicz (1609-1677), and other historians who added and modified various details [REF].