Some interesting nuggets in this article, including connections and locations in London.
The Hidden World of the Knights Templar
http://www.bbc.com/travel/story/20160510-the-hidden-world-of-the-knights-templar
FTA
In 1120, Christian knights had just captured Jerusalem in the First Crusade. But even while the holy city was safe, the pilgrimage routes to get there were not. Travellers were routinely attacked, robbed and even killed.
A handful of knights took monastic vows and devoted themselves to protecting the pilgrims and their routes. In return, the king of Jerusalem gave them headquarters on the Temple Mount. The Knights Templar was born and they were soon world-renowned for their courage.