Historian Pieter Geyl's opposition to a division in fifteenth-century painting in the Low Countries has been the subject of frequent discussion. This article presents the first examination of the motives of the two principal upholders of the theory repudiated by Geyl: Adriaan Pit and Willem Vogelsang. In 1894 Pit drew a sharper distinction than predecessors such as Bode and Moll between Dutch and Flemish fifteenth-century painting. Pit's position was based on his conception - which in turn was substantially influenced by Louis Courajod - of logic in art history. Pit's stance, which implied a division in the Netherlands prior to the Revolt, sparked off a debate that continues to this day and has been conducted by both historians and art historians. For most of his life Vogelsang presented himself as the foremost defender of the opinion that the division of the Netherlands was reflected in fifteenth-century painting. His loyalty to Pit was closely linked with his conviction that, in art history, the eye was superior to the document. In this case the difference between Dutch and Flemish painting was plain to see, and brooked no historical argument. For Vogelsang, the first professor in the field of art history in the Netherlands, the legitimacy of art history as an independent discipline was ultimately at stake in this debate.