The Birthplace of Chivalry

The Reach was the wealthy end of Westeros where possibly wealthy lords held tourneys to impress fair maidens so that songs could be written. But they also cleaned up the south of children and giants.

The Andals were war mongering invaders... not much knighthood there.

However, i do think that the FM who came in the south of Westeros were of andal stock. They certainly do not ressemble the FM of the northern tribes.
So both origins are not necessarily contradictory.

Agreed, I don't think there is anything weird in the conspiratorial sense going on here. I do, however, think it's an important indicator of how Andal and First Men cultures (if they were in fact all that different) interacted with one another in the early going.

We're given the impression that knighthood is an institution of relatively pure Andal/Faith origins. ( pieceofgosa , I think the Westerosi term "knight" refers primarily to status within the Faith, not a rough equivalent for a heavy mounted warrior. Mounted warriors have been fairly commonplace for a long time.) I think the establishment of chivalry in the Reach represents an intersection of faiths and cultures, with roughly equal influence by both First Men and Andals. I think this fits with the similarities knighthood bears to both the ancient Night's Watch, and closer to home, the Citadel's "knights of the mind."

This may provide some valuable information on how devotees of the Faith and the old gods have interacted over the millenia. Admittedly, I might just be way behind and all of this information may have been uncovered already, as I've only been reading the books since around 2011-12... Regardless, I think this dynamic is fascinating, especially since character motives are so often driven by old historical grudges/allegiances.

Powerfully worded my friend.

I also think it is interesting that the Seven pray to a seven sided crystal, alive with light. The whole thing evokes the Others, not just the Stranger. And the Stranger's face is but one of our own -- Mother, Father, Warrior, Smith, Maiden, Crone -- because the Seven are one. Sorry to go all Other-y. I do that too often.

I really like the idea of some Old Gods + Sevenist cross-mojination.

Mayhaps?

A pet theory of mine is that Andal warriors carved the seven-pointed star into their chests as a way of warding them against being raised as a wight after they fell in battle. It actually has a little bit of evidence from the text to support it:

That's a quote from Ser Bonifer the Good (he of the Holy Hundred) in Jaime 3 from AFFC & I think the implications are pretty clear, "armoured in his faith" c'mon ?