The reason King Taksin did not establish the capital at the old city was that Ayutthaya was vast. The royal palace had five tall and grand halls, and the temples and monasteries were all large. When the city had been largely burned and destroyed by the Burmese invaders and corrupt officials, Chao Tak, having only recently gathered his forces and restored his position, could not have the resources to repair such a large city and restore it as the royal capital. Moreover, if enemies invaded, there would not be enough troops to defend the fortifications, as the people were scattered in all directions and could not be gathered effectively (Royal Chronicles of the Old Capital: 70).

Regarding King Taksin’s relocation of the capital from Ayutthaya to Thonburi, Somdet Phra Borommaratchathera Krom Phraya Damrong Rajanubhab commented, “When considering the events recorded in later chronicles, it is seen that Chao Tak’s establishment of Thonburi as the capital was entirely practical. If the former king had come to prevent Chao Tak from settling in Ayutthaya, he did so with goodwill, warning him to avoid mistakes out of pride. Although Ayutthaya had a strategic location surrounded by rivers and strong fortifications, Chao Tak’s forces were insufficient to defend it against enemies, including the Burmese and other Thai factions, who could attack at any time. Ayutthaya’s location allowed easy access by land and water, so establishing the capital there with insufficient forces would have been dangerous. By setting the capital at Thonburi, not far from Ayutthaya, his authority was effectively as if it were in Ayutthaya, but with the advantage of Thonburi being on a deep river near the sea. Even if enemies approached by land without naval forces, it would be difficult to attack Thonburi. The city had fortifications, and its smaller size allowed Chao Tak’s army and navy to defend it. If it became indefensible, being near the river mouth allowed retreat by ship back to Chanthaburi. Strategically, establishing Thonburi was advantageous. Politically, it was also important, as Thonburi controlled the river mouth through which northern provinces traded with foreign countries, similar to Ayutthaya, preventing northern provinces aligned with other factions from obtaining military supplies abroad while allowing Chao Tak to access them easily.

For these reasons, establishing the capital at Thonburi allowed Chao Tak to assert authority over the northern provinces. Seeing these benefits, he chose Thonburi as the royal capital, and his decision was sound” (Thuan Boonyaniyom, 1970: 67-68).