"The Buildings" (, "Perì Ktismáton"; , "On Buildings") is a panegyric on Justinian's public works projects throughout the empire. The first book may date to before the collapse of the first dome of Hagia Sophia in 557, but some scholars think that it is possible that the work postdates the building of the bridge over the Sangarius in the late 550s. Historians consider "Buildings" to be an incomplete work due to evidence of the surviving version being a draft with two possible redactions.