In June 1846, thirty-three American immigrants in Alta California who had entered without official permission rebelled against the Mexican department's government. Among their grievances were that they had not been allowed to buy or rent land and had been threatened with expulsion. Mexican officials had been concerned about a coming war with the United States and the growing influx of Americans into California. The rebellion was covertly encouraged by U.S. Army Brevet Captain John C. Frémont, and added to the troubles of the recent outbreak of the Mexican–American War.