One driving force was the issue of slavery. In order to profitably farm the large tracts of land they had received from Mexico they needed Slave Power to prepare the fields, harvest the crops and ship them to market. Without that manpower their ability to prosper was limited. Mexico did not allow the slave trade and the Texicans wanted it. They had taken up the land knowing that two conditions were attached. # You were required to be a Catholic. There was no requirement to practice that faith but you could openly practice no other and were sworn to be a Catholic as a condition of receiving the land and becoming a citizen of Mexico. # As a good and loyal citizen and as a good Catholic you could not enslave others. All the Anglo Americans knew the rules and had taken the oath. Modern thinkers insist that other freedoms brought about the need for Independence but the facts do not support that position.