Building upon the previous work by F. Hueber and U. Outschar,1 this study offers new research on the Sebasteion’s significant architectural refinements, which can be defined as intentional design strategies resulting in minimal deviations from strict rectilinearity, verticality or squareness. The first part of this study identifies where the refinement of curvature is and is not used throughout the Sebasteion complex. A striking pattern of curvature corresponds to the well-documented shared patronage of the complex, demonstrating that the refinement was a choice, not an imperative, for its builders. We also report on a newly-excavated and remarkable example of curvature from the podium of the Sebasteion’s W façade, the Propylon, and for comparison’s sake, curvature in the earlier proskenion of the Theater. Using anastylosis, digital photogrammetry and 3D printing technology, the second part of this article presents new evidence for unprecedented refinements in the Propylon’s aedicular architecture. The plans of the two double-height aediculae and three internal staircases are not rigidly square or orthogonal, as previously thought, but deliberately deviate from having square corners using right angles. After detailed descriptions of these features, several options for their interpretation are presented. Overall, this work brings to light astonishing aspects of the architecture of the Sebasteion, a building already widely appreciated for its sculptures.