U Thong Dynasty: Ayutthaya's Founding Kings and Temples

The U Thong Dynasty: The Royal House of Ayutthaya's Founder

The U Thong dynasty was the royal house of the man who founded Ayutthaya. It produced only three kings and reigned in two separate periods, alternating with the Suphannaphum dynasty, for about 40 years in all. Although it did not hold power for long, many of the important temples you see in Ayutthaya today were begun in the reigns of this dynasty.

Kings of the dynasty (1351–1409 (not continuous))

No.	King	Reign	Key events
1	King Ramathibodi I (King U Thong)	1351–1369	Founded Ayutthaya, built his palace where Wat Phra Si Sanphet stands today, and built Wat Phutthaisawan and Wat Pa Kaeo.
2	King Ramesuan	1369–1370 and 1388–1395	Reigned twice: the first time he handed the throne to Khun Luang Pha-ngua; the second time he seized power back from King Thong Lan. Some versions of the chronicles say he built Wat Phra Ram, Wat Mahathat and Wat Phu Khao Thong.
5	King Ramrachathirat	1395–1409	Son of King Ramesuan. He was overthrown by Chao Nakhon In of Suphan Buri and sent to live at Pathakhucham, bringing the U Thong dynasty to a close.

Where the dynasty's name comes from

The U Thong dynasty takes its name from the name by which its first king is popularly known, King U Thong, who came to the throne with the title King Ramathibodi I. Some historians call this dynasty the Lavo line, because its main power base was Lopburi, which his son Ramesuan went to govern.

Suphan Buri, meanwhile, was in the hands of Khun Luang Pha-ngua, Ramesuan's uncle. The relationship between these two cities turned into a struggle for power that ran through the whole early period of the kingdom.

The reign of King U Thong (1351–1369)

King U Thong founded Ayutthaya in 1351 and built his palace on the spot where Wat Phra Si Sanphet stands today. Later chronicles say that early in his reign Ayutthaya's armies marched against Angkor, the Khmer capital, with Ramesuan and Khun Luang Pha-ngua taking part in the fighting.

In 1353 he had Wat Phutthaisawan built on the site of the Wiang Lek residence where he had lived before founding the city, and around 1357 Wat Pa Kaeo was built — the temple that later became Wat Yai Chai Mongkhon. King U Thong died in 1369.

Ramesuan's first reign, and his abdication

King Ramesuan came from Lopburi to succeed to the throne in 1369. According to some versions of the chronicles, he had Wat Phra Ram built on the site where his father had been cremated. But after reigning for only about a year he handed the throne to Khun Luang Pha-ngua and went back to rule Lopburi as before.

This abdication is often described as a willing one, but some researchers think he was more likely forced to step down because the Suphan Buri side was stronger. The Suphannaphum dynasty thus held the throne for about 18 years.

The second reign (1388–1395)

When King Borommaracha I (Khun Luang Pha-ngua) died on his way back from a campaign in the north in 1388, his son King Thong Lan came to the throne but reigned for only seven days: King Ramesuan came from Lopburi, seized the palace and had King Thong Lan executed at Wat Khok Phraya.

In this second reign, the chronicles say, he marched against Chiang Mai and fought the Khmer once again. Some versions of the chronicles also state that he had Wat Mahathat built in the centre of the capital and Wat Phu Khao Thong north of the city island. He died in 1395.

King Ramrachathirat and the end of the dynasty

King Ramrachathirat, the son of King Ramesuan, reigned from 1395 to 1409. During this time Ayutthaya's hold over the northern towns weakened: Sukhothai broke away and took back Nakhon Sawan, while Chao Nakhon In of Suphan Buri kept in close contact with the Ming court in China and gained great prestige.

In 1409 the king fell out with his chief minister, the Chao Senabodi, and ordered his arrest. The minister fled across to Pathakhucham and asked Chao Nakhon In for help. The Suphan Buri army captured the capital, King Ramrachathirat was sent to live at Pathakhucham, and so the U Thong dynasty came to an end.

Traces of the U Thong dynasty you can visit

Although this dynasty's reigns added up to only a short time, it laid the foundations of the palace and of many temples that you can still walk around today.

Wat Phra Si Sanphet and the Ancient Royal Palace: the site of King U Thong's first palace
Wat Phutthaisawan: built on the site of the Wiang Lek residence
Wat Yai Chai Mongkhon: originally Wat Pa Kaeo
Wat Phra Ram: built on the site where King U Thong was cremated (the chronicles disagree about who built it)
Wat Mahathat and Wat Phu Khao Thong: built by King Ramesuan, according to some versions of the chronicles

Where historians still disagree

Where King U Thong came from: the Thai chronicles say he moved here from the town of U Thong because of an epidemic; van Vliet's account says he was a Chinese merchant who had lived in Phetchaburi; Lanna sources connect him with Lavo; and some books suggest he already ruled an area near Ayutthaya. There is still no consensus.
The division into dynasties: the names U Thong dynasty and Suphannaphum dynasty are labels that historians use to group the kings, and some scholarly work has questioned how closely this division matches what really happened.
The length of Ramesuan's first reign: the royal chronicles say one year, but van Vliet's account says three years, and adds that he was deposed by his uncle.
The year Ramesuan returned to the throne: the Luang Prasoet Chronicle says Khun Luang Pha-ngua died in CS 750 of the Chula Sakarat era (BE 1931 / 1388), while chronicles of the Rattanakosin period say CS 746 (BE 1927 / 1384).
Who built Wat Phra Ram and Wat Mahathat: for Wat Phra Ram, some versions say Ramesuan began it while others say King Borommatrailokkanat built it later. For Wat Mahathat, the Luang Prasoet Chronicle says construction began under Khun Luang Pha-ngua, while later versions say Ramesuan built it.
King Ramrachathirat's reign dates: this article uses the years given in the Luang Prasoet Chronicle (1395–1409). Some later chronicles place his overthrow around 1401 and give lengths of reign ranging from 3 to 15 years.

Frequently asked questions

How many kings did the U Thong dynasty have?

Three: King Ramathibodi I (King U Thong), King Ramesuan and King Ramrachathirat. King Ramesuan reigned twice.

Why did the U Thong dynasty reign in two separate periods?

Because from 1370 to 1388 Khun Luang Pha-ngua of the Suphannaphum dynasty reigned instead, until King Ramesuan seized power back in 1388.

Did King U Thong really come from the town of U Thong?

There is still no consensus. The Thai chronicles say he moved here from the town of U Thong, but other evidence links him to Lavo or to Phetchaburi.

Last updated 10 November 2026