Complex sentence: What is certainly known of the events of that night is that the King and Queen were eventually discovered hiding inside a wardrobe, and then both savagely killed; their bodies mutilated, and afterwards tossed from a second floor window onto piles of manure.
Split into simpler sentences: What is certainly known of the events of that night is that the King and Queen were eventually discovered hiding inside a wardrobe and then both savagely killed. Their bodies were mutilated and afterwards tossed from a second floor window onto piles of manure.