In this article, the history of the Science of Religion in the Netherlands in the period 1860 to 1960 is surveyed at the time when it was an integral part of Dutch liberal academic theology as pursued in the faculties of theology at the universities of Leiden, Groningen, Utrecht and Amsterdam. In 1876, these faculties were given a special statute, the so-called Duplex Ordo, in a law that separated the ‘confessional’ theological disciplines from the ‘scientific’ ones. It also introduced the new disciplines of the Science of Religion and the Philosophy of Religion into these reconstituted faculties. I discuss Tiele's plan to make the Science of Religion their central discipline, and why it was ultimately given only a marginal place in them. My main concern, however, is to outline the theology which inspired the Science of Religion of Tiele, Chantepie, Van der Leeuw and Bleeker and to demonstrate its ‘close harmony’ with the liberal theology prevailing in these Duplex Ordo faculties, as also in at least some of the modalities of the Nederlandse Hervormde Kerk whose ministers were trained, again by law, in these faculties. It was that close harmony which allowed Van der Leeuw to disregard the Duplex Ordo and to establish a full harmony between the Science of Religion and confessional theology. I also discuss dissonant voices, Kraemer's especially, calling for the abrogation of the Duplex Ordo and the integration of the Science of Religion into a militantly confessional theology.