Third Crusade. He changed at that point.
No, sorry, those weren't Christians he burned. Saladin succeeded in uniting the many different nations/warlords/tribes of the area to confront the Christians, but he didn't do it all by sweet talk and gentle smiles any more than Mohamed dd. His goal was expanding Islam, and all Islam stood for. And the rules of war under Islam are fairly clear in being able to
****/enslave enemy women and behead enemy men.