Virtually every discourse in the medieval period was constructed around the ideal of balance. In my recent book, A History of Balance, 1250-1375, published this past spring by Cambridge Press, I show that preoccupations with balance lay at the core of medieval economic thought, medical theory, political thought, and natural philosophy, but one could apply the same analytic focus on balance to a host of other disciplines. And yet, in spite of the ubiquity of the concern with balance (or perhaps because of its utter ubiquity), it was almost never the subject of discussion in itself in the medieval period. For this reason modern historians, too, have failed both to recognize balance as a subject crucial to the history of ideas, or to imagine it as having a history – as changing in form over historical time. In my presentation, I will argue that an analysis of the forms of balance that were assumed and applied in the medieval period – and, in particular, an analysis of the change in the modeling of balance that occurred between 1280 and 1360 - are crucial both to the opening up of striking new vistas of imaginative and speculative possibility within scholasticism and to the scholarly comprehension of this many-faceted intellectual development.