In 1851, the colonial administration of the Dutch East Indies established a two-year program to educate young Javanese men to become vaccinators in Batavia (today's Jakarta). During the following sixty years, the medical curriculum was expanded several times; in 1913, it consisted of a ten-year program. In 1927, the Batavia Medical School, granting degrees equivalent to those of Dutch university-affiliated medical schools, commenced operations. Consequently, a steadily increasing number of Indonesian physicians with various credentials were employed by the colonial health service, plantations, sugar factories and mines, or established private practices. They became a social group that occupied an ambiguous and even paradoxical position somewhere between Europeans and the indigenous population. During the 1910s, this inspired these physicians to obtain credentials and professional recognition equal to those of their European colleagues. Several of them became active in journalism, politics and social movements. During the 1920s, several became radicalised and criticised the nature of colonial society. In the 1930s, following the increasingly repressive nature of colonial society, most of them remained active in the public sphere while a small group dedicated itself to improving medical research and health care. After the transfer of sovereignty from the Netherlands to Indonesia on 27 December 1949, this small cadre reestablished medical education and health care, and built the Indonesian medical profession.