What does "steeped in" mean here?

Maybe they left off Civilization from "the Indus Valley?"

This sentence is poorly written and does not use the phrase steeped in properly. To be steeped in something means to be surrounded or influenced by a quality or characteristic. I've never seen a usage where something was described as steeped in a place.

Ignoring the first clause, the sentence reads, "Steeped in the Indus Valley stood the very first towns and cities known to mankind." You can't even put any valid quality there like history or culture and have the sentence read properly - "Steeped in culture stood the very first towns and cities known to mankind" is still rather awkward.

This just doesn't seem like very good writing, as they also call Mesopotamia the "heart of Asia", even though it's thousands of miles away from what most people would call the Heart of Asia, closer to Afghanistan.