So I was thinking about the Starks and the Targs today. We know these are the two mystical families with certain powers. The starks with warging and the Targs have been known to have a strong gift for prophecy. You always hear Dany saying the targs are the blood of the dragons. I used to just ignore that as just bluster/bragging that houses do about their sigils. But what if way back before there were valyrians, that Dragons reversed warged. Like maybe the Valyrians ancestors were Dragons who warged into human form, and that gives the current valrians the ability to tame/control/ride dragons.
Just a thought.

maybe the valyrians and the first men are related in someway.