Tern) Ghamma Elame and Leto n Atreides The Book o/Ghanima RRC 13 A700 ATRElDeS, LETO I 64 ATREIDES, LETO I ATREIDES, DUKE LETO I (10140-10191). Last Duke of House Atreides to rule on Caladan; falter of Duke Paul Muad'Dib; prescribed over the change from Caladan to Arrakis. Duke Leto I was bom on Caladan in 10140, the only child of Duke Mintor out of the concubine Bekah, who died in delivery.