Leibniz’s commitment to Christianity has been questioned for centuries; even today, some scholars claim that he was inclined towards deism or little more than a pagan metaphysician. Such an interpretation seems prima facie to be at odds with certain Christianized features of Leibniz's work, such as his decision to advance a solution to 'the Jehoshaphat problem', the problem of whether (or how) all the humans who have ever lived can simultaneously fit into the valley of Jehoshaphat. This problem has its (...) roots in both scripture and Christian tradition, and is therefore one that would not be of concern to a non-Christian. Leibniz treated the Jehoshaphat problem twice in his work (in 1711 and 1715); I examine both of these treatments in depth, and consider what conclusions should be drawn from them with regard to Leibniz’s commitment to Christianity. (shrink)