The historiography of mathematics in the Renaissance involves two kinds of anachronism. First, the tendency to anachronism in the authors themselves, whose understanding of broad historical structures and of the development of mathematics may be colored by concerns of their own time. And second, our anachronism in reading these histories of mathematics as if they were attempting precisely the same thing as modern historians of mathematics. This article focuses on the author of the first modern work dedicated to the history of mathematics, Petrus Ramus (1515–1572), singling out three occasions in which his historical account seems to diverge widely from that of modern historians, and examining them in the light of both types of anachronism. First, in his account of the development of mathematics in the early Platonic Academy; second, his assessment of Eudoxus of Cnidus; and finally in his dating of the Neoplatonic philosopher and commentator on Euclid, Proclus.