Stone inscription No. 46 describes that the Queen Mother, together with her son "Satṃtec Mahādharrmarājādhipati Śrī Surīyavaṅsa" (Sai Luthai), recaptured Phra Bang (present-day
Nakhon Sawan) and
Phrae with her army in 762 C.S. (1400 A.D.) and then "enjoyed dominion over the entire land of
Sri Satchanalai and Sukhothai". The reconquest of Phra Bang interrupted the transport of goods from
Ayutthaya in a north-south direction. After the death of King in the northern neighboring kingdom of
Lan Na in 1401, Sai Luthai intervened in its succession dispute on the side of the King's eldest son, Thao Yi Kum Kam. He and his army marched into Lan Na. However, after seeing a bad
omen, he withdrew, took Yi Kum Kam with him, and left him one of his provinces (possibly
Kamphaeng Phet) as an
appanage. Lan Na was ruled by Yi Kum Kam's younger brother . When King
Intharacha ascended the throne of
Ayutthaya in 1409, one of his first actions was to reconquer Sukhothai as a vassal state. The exact date is unknown, but stone inscription 49 was written in 1412 by a Nai Inthara Sorasak, who was probably the resident of the king of Ayutthaya, sent to Sukhothai by King Inthara to secure Ayutthaya's interests against his vassal. After his death in 1419, his throne was passed onto his son,
Maha Thammaracha IV. ==Ancestry==