1395 - Ramesuan dies at 62 and is succeeded by his son Ramraja for 14 fairly peaceful but also uneventful years.
1409 - King Ramraja is deposed from his throne by Prince Nakonin, governor of Sysan and the son of a younger brother of King Boromaraja I. Nakonin later proclaims himself King with the title Intharaja.
1424 - King Intharaja dies and his three sons fight over the throne; two of them die. The youngest of the three brothers is the survivor and is proclaimed King of Ayutthaya with the title Boromaraja II.
1431 - After Cambodia has again gained kind of independence, a new war between Ayutthaya and Cambodia breaks out. It lasts for seven months during which Thai forces again invade Angkor. King Tammasok of Cambodia dies during the war and the King of Siam sets up his son, the Prince Intaburi as King of Cambodia. Intaburi dies after just a few months in office. Thereafter, Cambodia regains again its independence.
1432 - The Khmers vacate Angkor, considering it too close to the border with Siam and relocate their capital in Basan on the eastern side of the Mekong River.
1434 - The Khmers move their capital again, this time to Phnom Penh. In the course of history they will switch several times between the sites of Phnom Penh and Lawak near Phnom Penh.
1438 - Sukhothai is fully incorporated into the Siamese Kingdom of Ayutthaya. Prince Ramesuan is appointed governor of Phitsanulok.
1442 - Ayutthaya is at war with Chiang Mai. Chiang Mai suffers defeat but not to the extent that the Lannatai Kingdom of Chiang Mai is integrated into Siam or becomes a real vassal. However, the Ayutthaya forces again capture part of the Lannatai population and resettle the people in their own realm.
1448 - King Boromaraja II dies and the Prince of Phitsanulok, Ramesuan, becomes king of Ayutthaya. He assumes the title King Trailok. During his extraordinarily long rule of 40 years, King Trailok reforms the administrative system of Siam, giving it a stricter hierarchical structure. The system of nobility in Siam, too, is founded by King Trailok who creates seven grades of nobles. The grades of nobility from the highest to the lowest are: 1. Phaya, 2. Phra, 3. Luang, 4. Khun, 5. Muen, 6 Pun, 7. Tanai. An additional grade, topping the one of Phaya, is created later, the rank of Chao Phaya. In all of the history of Siam, the above ranks of nobility are not hereditary. The only hereditary rank is the one of prince or princess for the offspring of kings and princes. Ranks of nobility are given by the ruling king who also can take them back. Also non-hereditary are land possessions; while there are certain rules, established by King Trailok, concerning the granting of land to nobles according to their rank, land allocations are in principle at the discretion of the king.
1456 - Conflict with the Lannatai Kingdom of Chiang Mai is smouldering.
1462 - Sukhothai, temporarily occupied by forces of Chiang Mai, is regained by Ayutthaya.
1463 - As the only external conflict of his reign is with the Lannatai Kingdom, King Trailok of Ayutthaya transfers his capital to Phitsanulok in the north of his realm, leaving his son, Prince Boromaraja, in charge of Ayutthaya.
1465 - King Trailok enters a Buddhist seminary as a monk.
1471 - The first white elephant is captured in Siam. By future definition, white elephants in the realm are all owned by the king.
1474 - Open war between Chiang Mai and Ayutthaya breaks out once again. The ruler of Chiang Mai, Maharaja Tilok, has his army massacre all the members of the Siamese embassy. As the war again doesn’t produce a clear victor, Trailok of Ayutthaya and Tilok of Chiang Mai both agree to a peace settlement. In spite of the fact that the threat from the north is no longer eminent, King Trailok does not move his capital back to Ayutthaya and remains in Phitsanulok, leaving Ayutthaya under the control of his son, Prince Boromaraja.
