Prime Minister of Thailand Rajanubhab took over this role. In fact, the office most considered the precursor of that of the prime minister was the ancient office of "Samuha Nayok" (สมุหนายก), which was run by an "Akkhra Maha Senabodi" (อัครมหาเสนาบดี) or "chief minister in charge of civilian affairs". The first Prime Minister of Siam was Phraya Manopakorn Nititada, a judge. The title of the office was changed from "Prime Minister "of Siam"" to "Prime Minister "of Thailand"" in 1945 and then permanently with the renaming of Siam to Thailand in 1949. For most of its existence the office has been occupied by Army leaders;
João Tamagnini Barbosa João Tamagnini Barbosa João Tamagnini de Sousa Barbosa (30 December 1883 – 15 December 1948), commonly known as João Tamagnini Barbosa (), or Tamagnini Barbosa, was a Portuguese military officer and politician of the Portuguese First Republic (1910–1926). He served as Minister of Interior, Colonies and Finances during the period known as ""New Republic"", after the coup d'état of the National Republican Party ("Sidonist Party") and the semi-dictatorial government of President/Prime Minister Sidónio Pais, followed by a brief participation in the provisional government of João do Canto e Castro after the assassination of Sidónio Pais. He briefly served as Prime