While Alexander the Great is generally considered one of the Worlds Great Captains. He did fuck up a few times in the field just like everyone else.
One of these fubars was by marching his Army thru the dessert of South Iran. (Because his troops would not invade India and instead wanted to go home.So he punished them by doing this.)
Well as you can guess, The Army quickly ran out of water. But then a small amount was found and offered to the King. At the point old Al took the helmet full of water. Went to where everyone could see him and poured it out.
After that his troops would follow him anywhere.