In 1287, the Pagan Empire collapsed due to Mongol invasions, and all its vassal states became independent. In present-day Lower Burma, Wareru established a kingdom for the Mon-speaking people called Ramannadesa by unifying three Mon-speaking regions of Lower Burma: Martaban (Mottama), Pegu (Bago), the Irrawaddy delta. The kingdom's first capital was at Martaban but the capital was moved to Pegu in 1369.