PHILADELPHIA — Leonore Annenberg, the philanthropist and wife of late publisher and ambassador Walter Annenberg, has died. She was 91.A family spokeswoman says Annenberg died early Thursday at Eisenhower Medical Center in Rancho Mirage, Calif. The spokeswoman says Annenberg died of natural causes with her family at her side. Annenberg has headed the Annenberg Foundation since the death of her husband, publisher and ambassador Walter Annenberg, in 2002. She served as U.S. chief of protocol, a position that carries the rank of ambassador, during President Ronald Reagan’s first term.