Why were all the French Kings named Louis?

Factual Questions
1

Okay, so not all of them, but you know what I’m talking about. By the French revolution, the French were already on their 17th Louis.

Maybe a little understandable, after all, according to this site the monarchy went all the way back to 447.

But, you’ll also notice that between the years 1610 and 1795, every King was named Louis (not counting regents).

What’s up with that? Were the parents of these Louis so uncreative, or was there a real reason for naming all of them Louis? After a while, did it just become a tradition or something?

Thank you.

2

Wild guess on my part, but I suspect it was reverence for Saint Louis, the king during the Crusades. His crusade was a failure, objectively considered, but I think he imparted his aura of saintliness to the name.

3

But Saint Louis was Louis IX, IIRC. (i.e. Right smack in the middle of 1 and 17). So that would explain the last eight Louies, maybe, but not the first eight.

4

Actually, I saw a movie wherein a French child was asked if he knew his kings of France, and he replied “Yes, but I don’t know why I bother; ten are Charles, and the rest are Louis!”

5

Mostly, I believe it was a matter of tradition. The first Louis was the son of Charlemagne, who was the first Charles. From then on, it became accepted to name heirs Charles or Louis in reference to these two rulers.
Historically, Charlemagne was considered the first “French” king. Hence the numbering of kings starts with him.

Here is a list of French rulers. You’ll notice that kings not named Louis, Charles or Philippe are in minority.

One of the great thing, though is that many of them had nicknames, especially medieval kings. Some of the better ones:
Charles II le chauve (the bald)
Louis II le bègue (the stutterer)
Charles III le gros (the fat)
Louis V le fainéant (the lazy)
Louis X le hutin (the quarreler)
Charles VI le fol (the mad)