Kosa Lek
Kosa Lek was born to a Siamese woman Chao Mae Dusit in the Ayutthaya kingdom in 1632. Chao was a wet nurse for Phetracha, and also for Prince Narai on the following year, thus making Lek their foster brother. Kosa Lek and his younger brother Kosa Ban were important officials to Narai. When a group of senior lords who helped Narai to succeed to the throne had lost their power a group of young nobles led by Lek and his brother came to help Narai in their place. Lek served as a field general for Narai from 1660 to 1672, and was involved in the Burmese-Siamese War.
Lek became a minister and also a trader, and had a deep trade rivalry with one of the King's favorite Aya Muhammed Astarabadi of the Persian community until the latter being accused of corruption in 1677 and was executed by having his mouth sealed shut in October 1679.
Later Lek put a Greek adventurer and trader Constantine Phaulkon into his service to help facilitating his trading business. Impressed by his talent, Lek introduced him into the court of King Narai in 1681 and Phaulkon began to work as a interpreter. Phaulkon's ability to manage accounting and foreign affairs quickly gained the royal favor of the King.
In 1683, Lek had a disagreement with King Narai over the construction of a European-style fortress as suggested by Phaulkon. Lek was said to have received a bribe of 50 scales (about 4,000 baht in present days) from some certain phrai who did not want it built. King Narai had his men flog Lek with rattan sticks after which he died from his injuries about a month later.
Although King Narai grieved for Lek's death, this did not stop him from sending his men to confiscate Lek's properties, leaving his family with nothing. King Narai offered Lek's former position to Phaulkon, which he declined and instead accepted the advisory role to the Malay noble Okya Wang, who had assumed the position.
(Source: Wikipedia)