What policy was pursued by Alexander the Great in the conquered lands?

Alexander the Great in most cases in those conquered territories where the rulers did not resist him, but surrendered, left them in power. He was respectful of local gods and customs. For example, in the famous case of Egypt, Alexander willingly accepted the title of Pharaoh from the local priests and made sacrifices to Amon Raz.

In those regions where local residents actively resisted, the commander could resort to very cruel methods of punishment. For example, in the city of Tire, he crucified all the men who did not die during the siege.