Later Development
Sukhothai repopulated again but suffered from continuously urban decline due to successive Burmese–Siamese wars especially Burmese–Siamese War (1765–67). In 1793 Rama I, after establishing Bangkok as a new capital city of the Kingdom, found New Sukhothai in Thani, 12 km (7.5 mi) to the east of old Sukhothai, thus the fully abandoning Sukhothai. In 1801 Rama I commissioned the construction of many royal temples in the capital city, ordered that various old Buddha images should be brought to Bangkok from the ruined temples around the country. One of the Buddha images is the famous 8 metre (25 foot) tall bronze Phra Sri Sakyamuni , the principal Buddha image of Wat Suthat, which was the principal Buddha image of Wat Mahathat, the biggest temple in Sukhothai. In 1833 Mongkut, during his monkhood, travelled to Sukhothai and discovered the controversial Ramkhamhaeng stele in Wat Mahathat and other artifects, now in the National Museum in Bangkok. The formal name of this stone is The King Ram Khamhaeng Inscription Documentary heritage inscribed on the Memory of the World Register in 2003 by UNESCO.
In 1907 Vajiravudh as a crown prince, conducted a two month archaeological field trip to Nakhon Sawan, Kampheang Phet, Sukhothai, Si Satchanalai, Uttaradit and Pitsanulok. He later published "Phra Ruang City Journey" to promote historical and archaeological study among general public. The work has been used as structure by later archaeologists and historians including Damrong Rajanubhab, the founder of the modern Thai education system and George Coedès, a 20th-century scholar of southeast Asian archaeology and history.
In July 1988 the park was officially opened. On December 12, 1991, it was declared a World Heritage Site as part of the Historic Town of Sukhothai and Associated Historic Towns together with the associated historical parks in Kamphaeng Phet and Si Satchanalai.