The one and only King of Lithuania. I'm not sure if too much would have changed. He had managed to alienate a lot of the nobles by becoming Christian and then the Christians by not being particularly constant in holding to the religion. He flopped around when it was convenient. He was never christian enough to stop the Teutonic Knights and too christian for his nobles. He and his sons who were assassinated would have had to have been very lucky and/or gifted (preferably both) to have consolidated their hold. Mind you stranger things have happened OTL.