Architect J. Th. van Oyen designs numerous religious buildings in "the Dutch East Indies" during the interwar period. The demand for these is great. After the separation of (the Protestant) church and state by the Netherlands in the 19th century, there is a rise of Catholic missions in these Dutch colonies at the beginning of the 20th century. In this, Franciscus van Lith, a progressive Dutch Jesuit priest, plays an important role. It is in response to this religious expansion that Van Oyen receives commissions to design, for example, a monastery, a cathedral, several churches, and a friary house. For both the Roman Catholic Vincentius Society and the St. Camillus Foundation, he designs an (expansion of) an orphanage. Van Oyen maintained contact with Reverend Simon Beekman (1893-1974), who arrived in "the Dutch East Indies" in 1925. This is evident from several archival documents. For example, several photographs of Beekman have been preserved in Van Oyen's archives, as well as correspondence between the two and also Beekman's In Memoriam. Whether Beekman was Van Oyen's client is as yet unknown.