Simplify the following text for a Grade 10 native English-speaking person.
Original: Bishop withdrew from the conference in 1956 , Langston in 1957 and Huston-Tillotson ( formerly Samuel Huston ) in 1959 , one year after the admittance of two more state-supported schools : Grambling College and Jackson State College .
Simplified: Bishop withdrew from the conference in 1956 , Langston in 1957 and Huston-Tillotson ( formerly Samuel Huston ) in 1959 . That happened one year after two more state-supported schools entered the league ( Grambling College and Jackson State College ) .