I was busy updating Ban Borić article; added many new and reliable references. It should be obvious now that he, having been an illegitimate son of a Hungarian king, was also the first Viceroy of the then-newly created Banate of Bosnia, where he ruled as autonomous sovereign. Since he's the first first, then he is considered the founder of the House as well. The House is sometimes referred to as Boričević but this is probably just to honor him, because I've never heard of a one-man royal house? So I say we stick with Borić as the founder of the House of Berislavić (meaning House in historic/legal sense of course, or as royalty if you wish.)