The Irrawaddy River valley most impacted the formation of the Pagan Kingdom. The Kingdom itself in its earliest phases was but a small settlement that had entered into the valley from another kingdom, the Kingdom of Nanzhao, in the 9th century. They moved onward from this valley, slowly annexing neighboring settlement up until the 11th century. At this point King Anawrahta officially founded the Pagan kingdom, annexing all these settlements into one big kingdom.
