In June 1846, Frémont and Carson participated in a California uprising against Mexico, the Bear Flag Revolt. Mexico ordered all Americans to leave California. American settlers in California wanted to be free of the Mexican government and declared California an independent republic. The American rebels found the courage to oppose Mexico because they had Frémont, who had written an oath of allegiance, and his troops behind them. Frémont and his men were able to give some protection to the Americans. He ordered Carson to execute an old Mexican man, José de los Reyes Berreyesa, and his two adult nephews, who had been captured when they stepped ashore at San Francisco Bay to prevent them from notifying Mexico about the uprising.