Ekatotsarot, whose reign has seen the influx of foreigners into Siam as traders and mercenaries, has established Krom Asas (i.e., volunteer regiments) of foreign soldiers, for example; Krom Asa Mon, Krom Asa Cham, Krom Asa Yipun (Japanese mercenaries), and Krom Asa Maen Puen (Arquebusiers - the Portuguese and Dutch).
Ekatotsarot had a close relations with the Tokugawa shogunate under Tokugawa Ieyasu who has commissioned Red Seal Ships—armed merchant sailing ships bound for Southeast Asian ports with a red-sealed paten—to trade with Siam.
Around this time, the Siamese metallurgists learn the arts of forging mortars from the Westerners and combine these principles with traditional methods, giving rise to the Siamese mortars praised for their high quality of manufacture and design.
Ekatotsarot has two legitimate sons: Prince Sutat and Prince Sri Saowabhak.
Prince Sutat is invested with the title of Uparaja in 1607.
Only four months later, Prince Sutat asks his father to release a prisoner; but instead angers his father, who accused Sutat of rebelling.
The prince commits suicide by poison the same night—much to the grief of Ekatotsarot.
This is one of the most mysterious events of Siamese history, as no one knows who was the prisoner Prince Sutat tried to free, nor why Ekatotsarot was so angry.
Some historians have hypothesized that the prisoner was one of the powerful nobles whose power was a challenge to the monarchy.
The nature of Prince Sutat's death is also disputed, as he may have been poisoned by someone else.
Whatever the facts, the incident lays the ground for future princely struggles that are to plague Ayutthaya throughout the seventeenth century.
Ekatotsarot defies expectatrions by not appointing as Uparaja his second son, Prince Sri Saowabhak.
