It is sometimes argued that post-modern philosophy represents a radical break with the philosophical past in its repudiation of ideas of transcendence, metaphysics, truth and so on. However, a closer look at a number of mediaeval thinkers clearly shows that this idea of a radical break is something of an oversimplification.
The ideas of Nicholas of Cusa stand out here. According to him, God does not transcend his creation, because creation only exists because of the gratuity of God. Creation is thus radically contingent - a kind of free floating happening. We ourselves as thus radically contingent as well. Nothing exists for a reason.
Here we can see the beginnings of the post-modern in philosophical terms - the rejection of the principle of sufficient reason in the celebration of the irrational contingency of being. Moreoever, here we can see the origins of Heideggereanism and perhaps other philosophical movements as well (speculative realism resonates here too).