The mission hospital Trenggiling was founded by the Gereformeerde Zending on Central Java in 1914. This mission hospital was situated in Purbolinggo (Banyumas) and was supported by the Gereformeerde Kerk of Rotterdam and by the churches of Southern Holland. The medical doctor P. Rot settled in 1953 here as a missionary doctor.
Dr. W.L. Vogelesang (1880-1932) was medical doctor of the hospital of Poerbolinggo from its start to his death in 1932. He was promoted in ophthalomology in Amsterdam and worked with Schreuder in his hospital from 1907. Later on he founded the hospital in Solo. He was appointed by the Gereformeerde Kerk of Rotterdam. E.T. Kal (1911-1966) was missionary doctor in the hospital of Poerbolinggo in 1936. J.J.Miedema was also missionary doctor in this hospital, probably a long time and until World War II.
Poerbolinggo was a regency and district of the Residency of Banyumas in the province of Central Java. The regency has 419,000 inhabitants of whom 130 Europeans and 2,200 Chinese. The main town Poerbolinggo is situated on the railway (Gonggryp 1934, 1178).