When Cortés left Tenochtitlan in May 1520, he was the practical if not titular ruler of a great empire. When he returned in June, he was fish bait. He desperately tried to regain his former position, but to no avail. His people were prisoners, cut off from food, water and escape routes. Every day they went out to plead for peace or fight for control of the causeways, but for every Aztec they killed, 10 more appeared. The Aztecs destroyed the bridges to prevent the Spaniards' escape.