The Vaulted Apses of the Temple of Venus and Rome: Coffers Design and Visual Alignments

Abstract This research focuses on the geometrical analysis of the two vaulted apses of the Temple of Venus and Rome at the Roman Forum. The intrados of these vaults present a complex design based on the repetition of quadrangular coffers that gradually reduce and adapt their shape to the double-curvature surface. Their arrangement follows a particular division into meridian sectors and alternating rows, ensuring a uniform coverage of the intrados of the vault. The geometrical rule used to determine this specific design is difficult to determine. The work studies the general shape of the inner surfaces of the vaults and explores possible methods used to define the coffers’ design, with a special focus on visual alignment strategies. The approach combines direct observation, a review of relevant scientific literature, and a graphical analysis based on the results of a rigorous photogrammetric survey of the conserved portions of the two vaults.