Before his exile in the Netherlands in 1683 Locke had shown some first glimmmerings of interest in doctrinal theology in the mid-1670s, and these glimmerings had then probably been very significantly developed by several influences between 1679 and 1683 – the reading of Unitarian works in 1679 and perhaps in 1680, Locke's own increasingly biblically and patristically astute criticisms of Stillingfleet and Filmer and the reading that composition of these necessitated in 1681–3, and his discussions with Thoynard and Damaris Cudworth in the early 1680s. In exile in the Netherlands this burgeoning interest turned very rapidly into very deep interest indeed. Locke's correspondence, notebooks, journals, and book purchases in his first years in the Netherlands are filled with theology. Cudworth declared shortly after Locke's arrival that his time in the Netherlands had already ‘Certainly been Advantageous to you, since I cannot but Fancie … that you have learnt more Scripture there than ever you Knew in your whole life before’.

There are many reasons for this transformation. Theology was central to Damaris Cudworth, with whom Locke had just fallen in love. While it is likely that Locke supported the attempt at revolution in England in 1685 by helping to finance the ill-fated Monmouth rebellion, he very probably thought that he was destined to remain in exile for the rest of his life.