Dominikus Zimmermann's pilgrimage church of Our Lady and parish church of St Peter and Paul in Steinhausen, built between 1728 and 1733, is undoubtedly one of the most remarkable creations not only of Upper Swabian Baroque architecture. Architectural history has devoted considerable space to it, and yet there are important aspects that have remained unnoticed and unexamined.The first question that arises is that of the ovals on which the building is based, whereby two different versions need to be examined: the design drawing that the architect presented to his abbot client, and the completed building, which could be analyzed in detail for the first time thanks to a recently created precise measurement. In both cases, the result shows ambitious oval constructions that deviate from the usual practice, as well as two fundamentally different geometric approaches, the respective reasons for which are open to speculation.The second complex deals with peculiarities of perception. Here, one cannot help but accord the Steinhausen church a prominent position. Zimmermann designs the path into and through the church interior as a sequence of stations, each characterized by different expectations of what is to come-by illusory images of space that the viewer creates in his imagination based on what he can perceive from his respective vantage point. These images dissolve as one walks through the church, they change, expectations are in a state of constant metamorphosis, until finally the image of the last station coincides with reality.A concluding chapter is devoted to the question of whether, and if so, to what extent Zimmermann's Steinhausen spatial artwork can be said to have a dialectical constitution of architecture, and which dialectically related moments prove to be constitutive of a unity.