The Chola Empire is one of the most severely underrated pieces of history imo

Basically a South Indian dynasty which started off pretty small but managed to conquer and rule some significant parts of South east Asia around 900-1100 AD. They had one of the best navies in the world at the time.

But overall they were really big on trading and exploring. Thanks to them, western Asia and Europe could have access to Chinese goods, and vice versa.

Something about sea based empires is so cool to me