I have read that knighthood in the Middle Ages was a strictly Christian military or statehood affair. However, I’ve read examples of Jewish heraldry sporadically in Spain, England, etc. Was knighthood explicitly Christian in the Middle Ages?

The Middle Ages laughs at all notions of hard categories that never shall meet, and furnishes us with thoughts of "Yes, but no, but kinda, but..." As always, if anyone else would like to make their own contributions, please don't let this post stop you! More input is always welcome, as the Middle Ages are the best Ages.

While you wait for new stuff, OP, here's a few questions along the lines of Jewish knights in the Middle Ages:

u/reproachableknight examines the notion here and how fuzzy the borders get;
and in this thread, u/BookQueen13 examines the implicitly Christian nature of knighthood, while u/Guckfuchs looks outside the reaches of Christianity.