A Digital Approach to Revisiting the Byzantine Past of Al-Madrassa Al-Halawiyya in Aleppo

The architectural complex of the al-Madrasa al-Halawiyya in Aleppo, Syria, remains one of the most remarkable monuments in the centuries-old city. First founded as the Church of St. Helen in the sixth century to serve as the Cathedral of Byzantine Aleppo, the structure preserves evidence of a complicated building history. For example, the Cathedral was converted into a mosque in 1124; later, parts of the church were integrated into a Madrassa. More recently, damage to the structure due to the war revealed information about Byzantine building methods. This research revisits the building history of the monument by relying on a parametric, Building Information Modelling (BIM) representation to compare the surviving structure with earlier reconstructions., this paper addresses the following: 1. A survey of the building's history, topography, and architecture: Over the centuries, al-Madrasa al-Halawiyya has attracted Medieval monks, travellers, brigands, scholars, and more. Their accounts offer exciting opportunities to contextualise structural and functional changes to the complex. 2. An analysis of the historical structure, especially from the Byzantine period: The presented 3D documentation of the site focused on historical transformations, which the authors then traced and compared by means of BIM to reconstructions proposed by Samuel Guyer (1911) and Michel Écochard (1950). This research demonstrates how a hybrid methodology can be used to establish building phases for comparison with historical and scholarly accounts, revealing new knowledge about building techniques and processes. The presented work started with a field survey of the monument, which was used to generate a hybrid 3D point cloud. Using the point cloud, the Byzantine church was virtually reconstructed and several construction phases were identified. At the same time, H-BIM models were created based on the work of Guyer and Écochard. Finally, the Guyer and Écochard models were compared with the proposed Byzantine reconstruction and point cloud.