Athittayawong

Athittayawong was the shortest-reigning monarch of Ayutthaya, ruling for about 36 days in 1629 and often regarded as the last king of the Sukhothai dynasty.
Prince Athittayawong was a son of King Songtham. In 1629, following a coup led by Okya Siworawong, Athittayawong was removed from the throne, paving the way for Prasat Thong's accession.

The Puppet King

The ten-year-old child prince was raised to the throne by Siworawong. However, Siworawong continued to administer the country as Chaophraya Kalahom. After about a month, the government servants complained that there were in fact two rulers in the country, Athittayawong and Siworawong administering as a king, which could cause future danger for the country. They persuaded Siworawong to ascend to the throne so there would be only one king as per custom. Athittayawong was dethroned and Siworawong assumed the title Somdet Phrachao Prasat Thong.

Death

Athitayawong was executed at Wat Kok Phraya soon after being deposed, ending the Sukhothai dynasty. Siworawong ascended the throne as the first king of the Prasat Thong dynasty.