Interesting read. Between the Sultan being allowed to pray in the al-Aqsa mosque, being able to talk their way into ownership of Temple Mount, the denial of Christ in the initiation, and the designs on the inside of their chapel as opposed to religious imagery (reminded me of the inside of a mosque sort of), could they have been an underground Muslim movement? Kind of like the Muslim equivalent of the Jesuits?
A lot of people think the Templars were influenced by Sufi Islam and incorporated some of their thinking.
I thought of mohammedan “art”, as well, when I saw the chapel paintings.