The global Peter Lombard research reinaugurated in 1990s has resulted in a number of recent publications, but the Master of the Sentences’ theology proper is partially underresearched. In particular, a more detailed exposition of the distinctions 35-41 of his Book of Sentences is needed in order to clarify his doctrine of God’s knowledge and its relation to the human free will. The article builds on the earlier established evidence that, for Peter Lombard in distinctions 35-38, God’s knowledge, in general, is (...) not causative, although some causative power has to be ascribed to God’s knowledge of the good. The last part of distinction 38 and the content of distinction 39 further analyze the capacities and functionalities of the divine omniscience and explain how it interacts with acts of human will. The key question here deals with the problem of alternative states of affairs: whether something may be otherwise than God foreknew. As it is shown, Master Peter agrees that it is possible for created things and events to be otherwise than they are, but insists that God’s knowledge must be in any case exhaustive and infallible. He uses a number of logical tools to defend the thesis about God’s perfect knowledge and the possibility of things happening otherwise, but lacks a strict definition of the notion of “possibility” used here. The study concludes that in few cases Lombard’s posse could mean a potency or a simple logical possibility, or the diachronic contingency, but the overall theological statement is clear: potentially, God’s knowledge can be different or include alternative state of affairs but it cannot change. (shrink)