Complex sentence: He participated in the Papal conclave, September 1503, he made futile efforts to succeed Alexander VI, fighting against Cardinal della Rovere and Georges d'Amboise, the formal nominee of France.
Split into simpler sentences: He participated in the Papal conclave, September 1503. He made futile efforts to succeed Alexander VI, fighting against Cardinal della Rovere and Georges d'Amboise, the formal nominee of France.