Lord Valentine's Castle

Lord Valentine's Castle was written by Robert Silverberg and originally published in 1980 by Harper & Row.

Publisher's Summary
He is a man with no past—a wanderer without memory of his origins. He calls himself Valentine. As a member of a motley group of entertainers, he travels across the magical planet of Majipoor, always hoping he will meet someone who can give him back what he has lost.

And then, he begins to dream—and to receive messages in those dreams. Messages that tell him that he is far more than a common vagabond—he is a lord, a king turned out of his castle. Now his travels have a purpose—to return to his home, discover what enemy took his memory, and claim the destiny that awaits him…