Bayek, the main guy of the upcoming Assassin's Creed: Origins, is (as far as I know, anyway) the "original Assassin." And you can't have an Assassin's Brotherhood without a Templar Order, right? Or in this case, as is thematically appropriate, their progenitors, The Order of the Ancients.
The video doesn't explicitly state that the Ancients are the proto-Templars, but it seems obvious enough to me. They lust for power, they pull strings from the shadows, they wear cool headgear, and they are utterly in control and unassailable in every possible way—except for that one guy, who always seems able to spoil their parties at the worst possible moment.
A few commenters on YouTube have pointed out that Cleopatra, in Assassin's Creed canon, was actually supported by the Templars and eventually offed by an Egyptian Assassin, Amunet. But her death occurred in 30 BCE, 19 years after the events of Origins, and that's a lot of time for political leanings to evolve. It also sets up a possible betrayal twist somewhere in the game, although that's probably a little too obvious—at least until the inevitable Assassin's Creed: Origins - Cleopatra Rising DLC.
(I just made that up. There is no such DLC.)
Assassin's Creed: Origins comes out on October 27. We recently got some hands-on with the game that you can dive into right here.