Kosa Lek (Thai: โกษาเหล็ก, 1632 – July 1683) was a Siamese trader, field general and minister. He was the older brother of Kosa Pan and Thao Sri Chulalak, the concubine of King Narai.

Kosa Lek
Minister of Foreign Affairs and Trade of Ayutthaya
In office
Preceded byAqa Muhammed Astarabadi
Succeeded byOkya Wang
Personal details
Born1632 (1632)
Died1683 (aged 50–51)
RelativesKosa Pan (brother)
Thao Sri Chulalak (sister)
Military service
Allegiance Ayutthaya Kingdom
Years of service1660–1672
Rankfield general
Battles/warsBurmese–Siamese War


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.[1] Kosa Lek and his younger brother Kosa Pan 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 Aqa Muhammed Astarabadi of the Persian community until the latter was accused of corruption in 1677 and 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.[2] 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.[3]

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.[4]


  1. ^ "History of Ayutthaya - Temples & Ruins - Wat Samana Kottharam". www.ayutthaya-history.com. Retrieved 2020-04-27.
  2. ^ Keat Gin Ooi (2004). Southeast Asia: A Historical Encyclopedia, from Angkor Wat to East Timor. ABC-CLIO. pp. 1070–. ISBN 978-1-57607-770-2. Retrieved 27 April 2020.
  3. ^ John, Smith (2019). "State, Community, and Ethnicity in Early Modern Thailand, 1351-1767" (PDF).{{cite web}}: CS1 maint: url-status (link)
  4. ^ Ruangsilp, Bhawan (2007). Dutch East India Company Merchants at the Court of Ayutthaya. Boston: Brill. pp. 118–120. ISBN 9789004156005.