Original sentence: About the same period, southward-migrating Burmans took over lands in central Myanmar once dominated by Pyu city-states and established the kingdom of Bagan
Edited sentence: About the same period, southward-migrating Burmans took over lands in central Myanmar and established the kingdom of Bagan.Northern Burma was a group of city-states in a loose coalition.The 'King' of each city-state would change allegiance as he saw fit, so throughout history, much of the Shan-Tai north has been part of the Tai countries of Sipsongpanna, Lanna (a kingdom centered in Chiangmai, Thailand), Ayutthaya (old capital of Siam) and even affiliated with Laos