A son of Borommarachathirat I and member of the House of Suphannaphum, Thong Lan succeeded his father to the throne of Ayutthaya in 750 LE (1931 BE, 1388/89 CE) at the age of 15.

[6] Historian Suchit Wongthet (Thai: สุจิตต์ วงษ์เทศ) expressed the opinion that lan here is an old Thai–Lao term which encyclopediae say refers to "eel trap made of bamboo".

[7] The Bradley Chronicle, however, says the name of the boy king was Thong Lan (Thai: ท้องลั่น; IPA: [tʰɔ̃ːŋ˦˥.lä̃n˥˩]; "cry of stomach").

[12] Thai chronicles state that Thong Lan was 15 years of age when he ascended the throne in 750 LE (1931 BE, 1388/89 CE).

Ramesuan had Thong Lan put to death at a Buddhist temple called Wat Khok Phraya (Thai: วัดโคกพระยา).

[10] Thong Lan was killed by hitting his neck with a Sandalwood club, a traditional means for executing a royal person.

[19] Historian Damrong Rajanubhab introduced a theory that Boromrachathirat I brought his army to Ayutthaya in 732 LE because of certain political problems that Ramesuan was unable to deal with.

Suchit Wongthet (Thai: สุจิตต์ วงษ์เทศ) expressed the opinion that Boromrachathirat's arrival in Ayutthaya with troops was apparently to "seize power by means of military force (called coup in our days)" and Ramesuan returned to Lop Buri just to accumulate more power and wait for an opportunity to strike back.