The decline in Indigenous military resistance during this time shifted the mission of Fort Sill from cavalry to field artillery. During the 1890s, the post declined in importance, and was considered for closure, with the land being given to the Chiricahua Apaches, The first artillery battery arrived at Fort Sill in 1902 and the last cavalry regiment departed in May 1907. The artillery units required more facilities, so plans were made to replace the original structures with modern buildings. However, William H. Taft, then Secretary of War, intervened to save the original buildings. He ordered the fort to expand to the south and west.