The Pagan Empire disintegrated and anarchy ensued . The Mongols , who probably preferred the situation , did nothing to restore order in the next ten years . In March 1297 , they accepted the voluntary submission of King Kyawswa of Pagan although he controlled little beyond the capital city of Pagan ( Bagan ) . But Kyawswa was overthrown nine months later , and the Mongols were forced to intervene , leading to their second invasion in 1300 – 01 .