Why was the Bear Flag Republic formed and When did John C. Fremont led a revolt against Mexico?

During the Mexican War, American explorer John C. Fremont (1813-1890) led a revolt against Mexico in Sonoma, California.

With no support from the rest of the province, Fremont and other American settlers declared California an independent republic on July 4, 1846. The republic, which flew a bear flag, was short-lived.

A few days later, the rebels turned their “country” over to the United States, and the bear flag was replaced with the American flag.