About House Valentione...

[Anonymoose]

If they are, does that mean that there are many more noble houses/families than the ones on Ishgard's flag?

The four on the flag are the High Houses of Ishgard, implying that there are lower families. The four High Houses are descended from the knights who stood with Haldrath, the first Azure Dragoon, son of Thordan, founder of Ishgard.

What kind of political power/influence can they hold compared to the major 4 ones?

Considerably less. Even House Dzemael commands slightly more power than the other three high houses (at least at the moment).

Here are some big hints as to how the system works:

House Dzemael is said to be lorded over by a count; since Dzemael is about as high as it gets, this may be about as high as you can go before entering Holy ranks. In 1.0, a levequst referred to a Duke - how that guy fit into it, I have no idea. Isn't Duke higher than Count?

House Durendaire calls its banners to retake the Stone Vigil, and Cailean refers to himself as a bannerman of House Haillenarte, whose master is his liege lord. The big question is whether the High House's bannermen are carrying that house's banners or the banners of houses that are sworn to the high houses. There's very little context about that part. It sounds like some lower houses have sworn fealty, not directly to the archbishop, but to the high houses under him. It sounds like a distinction without much meaning, but spend some with Game of Thrones and you'll figure out how important that distinction is. And a levequest did once refer to Ser Jeorge of House Martynn...