This essay focusses on the changing critical identity of the Dutch modern art-and architectural historian in the decades after the Second World War ranging from the 1950s to the early 1990s. By adopting the historisation of De Stijl as a case-study I will state that its post war historiography was not only defined by new insights concerning this avant-garde movement, but equally by a change in the subject position of the historian as a critical actor. In this article the changed relationship between the subject (the historian) and the object (the past) is analysed as the exchange of an engaged attitude for a more detached position in which the past increasingly became the focus of an exclusive cognitive concern. However, this did not mean its results remained unchallenged. In fact, the epistemic turn described in this article went in hand in hand with the rise of postmodernism in the humanities, leading to relativistic claims concerning historical knowledge. Also, an already critical history was further challenged by the arguments of feminist historians. In this way, a univocal history of art was fragmented into a plurality of historical practices. Although these practices were no longer overtly politically engaged they remained politically implicated as the result of the complex correspondences between past and present that remained a part of the histories of artistic modernism.