Philip of Macedon

Here is a question asked out of ignorance, which I hope one of the leaned
members of our august List will be kind enough to answer. I have see King
Philip's name explained (in transliteration, of course) as "fil-hippo" or
similar, meaning "lover of horses". That looks like pure folk-etymology to
me - at the very best!. Is there any genuinely credible evidence that he
was given his name for that reason? Were kings of the period and of the
region called by their personal names, anyway, or were they called by
titles, perhaps? I ask the same of his son Alexander - or "Alek-sander" as
I have seen it in an English transliteration. The latter does look vaguely
like a title from earlier times, to me, and the former looks like
folk-etymology at work again. Any opinions on the List?

Thanks.

Gordon Barlow