In 1569 the Myanmar king Bayinnaung (reigned 1551–81) conquered Siam and placed Naresuan’s father, Maha Thammaracha, on the throne as his vassal. The capital, Ayutthaya, was pillaged, thousands of Siamese were deported to Myanmar (Burma) as slaves, and Siam then suffered numerous invasions from Cambodia. At the age of 16 Naresuan was also made a vassal of Myanmar and appointed governor of...