Complex sentence: The Mameluk sultans were drawn from the enfranchised slaves who formed the court and officered the army, and were mostly unable to form a new dynasty, usually leaving behind infants who were then overthrown.
Split into simpler sentences: The Mameluk sultans were drawn from the enfranchized slaves who formed the court and officered the arm. The sultans were unable to effectively form a new dynasty, usually leaving behind infants who were then overthrown.