well, here's an interesting thing. when you google "beau seant" (with a space) you get a handful of sites which claim the meaning is "be noble" or "be glorious".

but Google, as is its wont, asks: Did you mean: "beauseant"?

if you take that link you get a whole bunch more links which specify that "beauseant" is the *name* of the Templar banner

The Beauseant

from the archives of The Most Revd. Gary Beaver KGCTJ

"Our Order adopted a striped white and black banner, called the Beauseant, after the original piebald horse; and this word also became the battle-cry."

..I don't know, maybe we don't want to delve too much further into this eldritch Templar... <arrggghhhh.....>