In the third siege of Ayutthaya (1568–1570), Bayinnaung was able to conquer the kingdom and installed Maha Thammarachathirat as a vassal king. After six years of captivity, Prince Naret and his brother the White Prince were released to Ayutthaya, in exchange for their sister Suphankanlaya becoming Bayinnaung's secondary wife in 1571.[2]:63,67,75
While in Burma, "he followed the best of Burmese military training," studying alongside the "elite of Burmese youth, sons of princes and nobles." "Besides being gifted in military prowess, Naresuan who was highly intelligent, gained a great deal of general knowledge of the times.