Pioneers and Before By rsylvestri1189 Aug 13, 1521 Spaniards conquer the Aztecs Jul 11, 1598 Spanish settlers arrive in New Mexico Jun 1, 1690 First Spanish mission in Texas Jul 14, 1769 First Spanish mission in California May 20, 1862 The Homestead Act of 1862 May 10, 1869 The first Transcontinental Railroad was built