Ayutthaya was a prosperous district under the rule of the Kings of Sukhothai during the period that Sukhothai dominated Siam. Gradually Sukhothai lost control fo the region. King U-Thong, the ruler of U-Thong city, took the opportunity to move his people to Weing Lek (this area is the site of Wat Putthai Sawan) in the district of Ayutthaya. He did this because his people suffered greatly from disease and drouht in their old city. Following the unsuccessful attempt by Ler Thai's troops to retake the Ayutthaya district for Sukhothai, the king declared independence from Sukhothai. King U-Thong, who became known as King Ramathibodi I made Ayutthaya his capital city in 1350 A.D. He built his palace in the Nong sano district.