In 1829 , when Mexico abolished slavery throughout Mexico , the immigrants from the U.S. were exempted in some colonies .
In 1829 , when Mexico abolished slavery throughout Mexico , the immigrants from the U.S. were actively evaded governmental efforts to enforce this abolition in the territory .
In 1829 , when Mexico abolished slavery throughout Mexico , the immigrants from the U.S. were exempted in some colonies or actively evaded governmental efforts to enforce this abolition in the territory .