The history of slavery in Texas began slowly at first during the first few phases in Texas' history. Texas was a colonial territory, then part of Mexico, later Republic in 1836, and U.S. state in 1845. The use of slavery expanded in the mid-nineteenth century as White American settlers, primarily from the Southeastern United States, crossed the Sabine River and brought human beings they had enslaved with them. Slavery was present in Spanish America and Mexico prior to the arrival of American settlers, but it was not highly developed, and the Spanish did not rely on it for labor during their years in Spanish Texas.