Many historians reject quantitative methods as inappropriate to understanding past societies. This article argues that no sharp distinction between qualitative and quantitative concepts can be drawn, as almost any concept used to describe a past society is implicitly quantitative. Many recent advances in understanding have been achieved by deriving quantitative evidence from qualitative evidence, using the two dialectically, and indexing them against other quantitative findings from the same population. We show that this triangulation method can be extended to many apparently qualitative sources. Despite its successes, the potential of turning qualitative into quantitative evidence has only just begun to be exploited.