The first time Kytheon planeswalked to Bant, the knight captain Moukir asked his name  but could not understand the Theros native. She thought he had said Gideon and, from there, the name Kytheon was lost - paralleling the experience of many real world immigrants. When Gideon died at the hands of Nicol Bolas, he was sent to the afterlife of his homeplane where his name was restored