Texas, which had been settled by colonies of Americans, fought a successful war for independence from Mexico in 1836. Mexico refused to recognize the independence and warned that annexation to the United States meant war. Annexation came in 1845 and the Mexican–American War began in 1846. The American military was easily triumphant. The result was the Mexican Cession of Santa Fe de Nuevo México and Alta California. About 60,000 Mexicans remained in the territories and became US citizens. France took advantage of the American Civil War (1861–65), using its army to take over Mexico. Due to defeats in Europe, France pulled out troops, leaving the Imperialists and Maximilian I of Mexico to face defeat from the Benito Juarez-led Republicans (backed by the US).