Sources of Water

Lord Parker would send a messenger the very next morning towards Alexander's lines, who would come bearing a white flag on a luxurious horse, urging the legionnaires that they should surrender or they would have their water supply cut off.

This man, most likely a noble given how well dressed he and his horse were, addressed the men on the walls as such, 

"Men from distant lands! Surrender!"

"You have fought well, but my lord is the master of your provisions. He has control over your food. He has control over your water. He has control over your fate. Surrender! There can be no hope for you. Surrender! And all of you will be treated accordingly."

Despite the boisterous words and bold claim, the man was of course rebuked, with the answer being given only in the form of a shot from one of the crossbows that landed accurately just a few paces short of his horse.