Abstract The collection contains six commemorative, stamped and canceled envelopes celebrating the California Republic sesquicentennial anniversary in 1996. Envelopes include: Bear Flag Sequicentennial Committee, with Bear Flag raising ceremony in the Sonoma Plaza illustration; Mariano Guadelupe Vallejo, with Lachryma Montis (Vallejo's Sonoma home) illustration; Sum-Yet-Ho (Solano), Chief of Suysunes tribe; Bear Flag creation at Sonoma Barracks; John C. Frémont and the "Bear Flag" Battalion, June...