Complex sentence: Her remaining allies are defeated and her son is assassinated by Cesare, and the sulphur needed to make gunpowder dries up all over Italy when the Pope, through a Jewish trader and ally, manages to buy the entire supply, which he then grants to Cesare.
Split into simpler sentences: Her remaining allies are defeated and her son is assassinated by Cesare. The sulphur needed to make gunpowder dries up all over Italy when the Pope, through a Jewish trader and ally, manages to buy the entire supply, which he then grants to Cesare.