After months of research into Kerry's ancestry, Burke's Peerage, experts on British aristocracy, reported Monday that the Vietnam war veteran is related to all the royal houses of Europe and can claim kinship with Czar Ivan "The Terrible," a previous Emperor of Byzantium and the Shahs of Persia. Burke's director Harold Brooks-Baker said Kerry had his mother, Rosemary Forbes, to thank for most of his royal connections. "Every maternal blood line of Kerry makes him more royal than any previous American president," Brooks-Baker said.