Ottoman documents show us that there was a special architectural institution attached to the palace called the Hassa ‘Mimarlar Ocagi (Imperial Body of Architects). When this institution was created is not clear but we know it was already in existence before 1525. It was linked to the sehremini (the person then responsible for the financing, purchasing and administrative activities related to construction works).’ The Hassa Chief Architect was in charge of its administration. The first chief architect is believed to have been Acem Alisi (Alauddin). The chief architect was assisted by the water supply director, the chief of apprentices, the chief limeworker, the warehouse director, the first secretary of the warehouse, the first architect, the deputy architect, the director of repairs, and many master architects, qualified builders, foremen and artisans, as well as officers in charge of monitoring their activities. The institution was in charge of practically everything related to the empire’s civil engineering, architecture and urban development activities: water supply, sewer system, roads and pavements, building regulations, permits and control, as well as fire prevention, the activities of architects, foremen and superintendents and their wages, the standardisation of building materials and their quality and price control. It was also in charge of designing, erecting, maintaining and repairing buildings belonging to the Imperial family, high-ranking state officials, and of appointing architects, foremen and superintendents to those tasks. It was responsible for the construction of bridges, forts and other military works in times of war. Finally, it functioned as an educational institution, being in charge of the, further training of the most promising youths among those recruited by the devsirme (levy of Christian children for the janissary Corp and other State services).
Building projects were first developed as sketches or models, then submitted to the palace together with their cost estimates. Before construction began, someone was appointed responsible for the building, who would be in charge of building materials and workers, and who would regularly note down the expenses incurred. For important projects, the palace would be directly approached for the procurement of material and staff. In the provinces, the kadis (who functioned both as judge and mayor) would inform the palace of their building requirements and the latter would then give orders to the chief architect. In imperial buildings, young devsirme recruits, palace artisans (Ehl-i Hiref), payed workers and foremasters worked along with prisoners of war and convicts. Both Muslims and Christians could be employed. If necessary, architects would be sent to different provinces and sometimes abroad. Muslim rulers in India are known to have asked Ottoman Sultans to send them architects, and some of Sinan’s students were indeed sent there.
It is thought that the Imperial Body of Architects developed dramatically during the time of Sinan when it was restructured in order to handle the then frantic building activity. Provincial organisations attached to the palace or functioning under its control are known to have existed. The institution lasted for some 350 years, until it was integrated into the municipality in 1831.