first time the Persian army had been defeated with the King present on the field. Darius left his wife and an enormous amount of treasure behind as his army fled. The greed of the Macedonians helped to persuade them to keep going, as did the large number of Persian concubines and prostitutes they picked up in the battle. Darius, now fearing for both his throne and his life, sent a letter to Alexander in which he promised to pay a substantial ransom in exchange for the prisoners of war, and agreeing to a treaty of alliance with and the forfeiture of half of his empire to Alexander. Darius received a response which began "King Alexander to Darius". In the letter, Alexander blamed Darius for his father's death and claimed Darius was but a vulgar usurper, who planned to take Macedonia. He agreed to return the prisoners without ransom, but told Darius that he and Alexander were not equals, and that Darius was to henceforth address Alexander as "King of all Asia". Darius was also curtly informed that, if he wanted to dispute Alexander's claim to the Achaemenid throne, that he would have to stand and fight, and that if he instead fled, Alexander would pursue and kill him. By this, Alexander revealed for the first time that his plan was to conquer the entire Persian Empire. Siege of Tyre The Siege of Tyre occurred in 332 BC when Alexander set out to conquer Tyre, a strategic coastal base. Tyre was the site of the only remaining Persian port that did not capitulate to Alexander. Even by this point in the war, the Persian navy still posed a major threat to Alexander. Tyre, the largest and most important city-state of Phoenicia, was located both on the Mediterranean coast as well as a nearby Island with two natural harbors on the landward side. At the time of the siege, the city held approximately 40,000 people, though the women and children were evacuated to Carthage, an ancient Phoenician colony. Alexander sent an envoy to Tyre, proposing a peace treaty, and asked to visit their city and offer sacrifices to their God Melqart. The Tyrians politely told Alexander that their town was neutral in the war, and that allowing him to offer sacrifices to Melqart would be tantamount to recognizing him as their king. Alexander considered building a causeway that would allow his army