Mel should direct but not act, with Polish and Austrian unknowns playing the leads, and all dialogue in Polish, German and Turkish.
Knights of the West throwing the Muslim Janissaries of Suleyman the Magnificent back from the gates of Vienna? I'd pay to see that.
Yes this is key to success, this is why I enjoyed to watch “Apocalipso”. Mel is quite independent from Hollywood, he is the right man to do it.