The samuhanayok (Thai: สมุหนายก) was one of the two chief ministers in the historical Chatusadom government system of Siam (now Thailand), originally charged with civil affairs but later overseeing both civil and military affairs in northern cities. During the Ayutthaya and Thonburi periods, the official who held the post usually took the noble title of Chakri (Thai: จักรี, RTGS: Chakkri).[1] The term, from Sanskrit चक्री cakrī, literally meant "one who has a discus", referring to the Hindu god Vishnu who possesses the discus Sudarshana).
The last office-holder to be known by the title Chakri was Thongduang, who established the Rattanakosin Kingdom and became King Rama I in 1782. His dynasty, which includes the current Thai royal family, is known as the Chakri Dynasty after his former title. Later office-holders of Rattanakosin were granted individualized titles.[1]