Domestic policies in King Narai's reign were greatly affected by the interference of foreign powers most notably the Chinese to the north, the Dutch to the South, and the English who were making their first forays into India to the west.
Policies revolved around either directly countering the influence, or creating a delicate balance of power between the different parties.

In 1660, the Chinese invaded the Burmese capital at Ava to capture Zhu Youlang, the last Southern Ming emperor.
Sensing a possible weakening of Burmese influence in the northern vassal states, King Narai began the Burmese–Siamese War of 1662–64 to bring Chiang Mai under the direct control of Ayutthya.
Although the expedition was successful in taking control of Lampang and other smaller cities, a second expedition had to be conducted to bring Chiang Mai under control in 1662.
After stopping a Burmese army incursion in 1663 at Sai Yok, Narai led an army of 60,000 in an invasion of Burma, capturing Martaban, Syriam, Rangoon, Hongsawadi, and then in 1664 laid siege to Pagan.
After "causing many casualties in dead and wounded and capturing many prisoners of war", the Siamese retreated.

Narai also handed over control of Mergui to French officer Chevalier de Beauregard and his small French garrison.
At the same time, he also granted a concession of the strategic port of Bangkok to Beauregard, with the view of countering Dutch influence.

King Narai also built a new palace at present-day Lopburi ("Louvo" in the French accounts) utilising the expertise of Jesuit architects and engineers.
European influences are clearly evident in the architectural style, especially the use of wide windows.
The move to Lopburi was arguably prompted by the Dutch naval blockade of Ayutthaya in 1664 to enforce a fur monopoly.
Domestic policies in King Narai's reign were greatly affected by the interference of foreign powers most notably the Chinese to the north, the Dutch to the South, and the English who were making their first forays into India to the west. Policies revolved around either directly countering the influence, or creating a delicate balance of power between the different parties.
In 1660, the Chinese invaded the Burmese capital at Ava to capture Zhu Youlang, the last Southern Ming emperor. Sensing a possible weakening of Burmese influence in the northern vassal states, King Narai began the Burmese–Siamese War of 1662–64 to bring Chiang Mai under the direct control of Ayutthya. Although the expedition was successful in taking control of Lampang and other smaller cities, a second expedition had to be conducted to bring Chiang Mai under control in 1662. After stopping a Burmese army incursion in 1663 at Sai Yok, Narai led an army of 60,000 in an invasion of Burma, capturing Martaban, Syriam, Rangoon, Hongsawadi, and then in 1664 laid siege to Pagan. After "causing many casualties in dead and wounded and capturing many prisoners of war", the Siamese retreated.
Narai also handed over control of Mergui to French officer Chevalier de Beauregard and his small French garrison. At the same time, he also granted a concession of the strategic port of Bangkok to Beauregard, with the view of countering Dutch influence.
King Narai also built a new palace at present-day Lopburi ("Louvo" in the French accounts) utilising the expertise of Jesuit architects and engineers. European influences are clearly evident in the architectural style, especially the use of wide windows. The move to Lopburi was arguably prompted by the Dutch naval blockade of Ayutthaya in 1664 to enforce a fur monopoly.
Narai