Hungarian sources from 1288 make notice of one Russian named Ivan (Iwan dicto Oroz) as an ally of the ban of Severin, Theodore Vejtehi from the kindred Csan*d, who was one of the nobles that opposed the rule of Charles I of Hungary in 1316--1317. The land to the south of Severin was governed for Bulgaria by the despot of Vidin, Michael Shishman, a supporter of Vejtehi. Thus, as the Hungarian king established his authority over Severin and suppressed Vejtehi's rebellion, Ivan the Russian may have fled to Vidin and entered the service of Michael Shishman.
Severin
Vejtehi