In order to reconstruct the history of Justiniana Prima, it is fundamentally important to systematise and analyse the existing source information about this city. Undoubtedly the most difficult task is to conduct a more thorough examination of Procopius of Caesarea's account, devoted to the origin and native country of Justinian, included in Book IV of his work De aedificiis. This is due to the fact that it is a fragment of an extensive account of Justinian's building activity in Europe, which in turn is part of a book presenting all of his building achievements in the Empire. So far it has been underestimated how useful an analysis of the information on Justiniana Prima can be for becoming more acquainted with Procopius’ technique and methods of work. It should be emphasised that in this case we have a completely unique opportunity to confront his account with the data recorded in the legal acts regarding matters personally close to Emperor Justinian. Establishing the Emperor's attitude to Procopius and his work is, after all, certainly very important for understanding the circumstances of writing and the credibility of De aedificiis, and the description of Justiniana Prima provides an opportunity to supplement general observations about this account with direct references to other sources.

At the moment, there exists neither a historical analysis of De aedificiis nor a relatively comprehensive description of this work which would take into account the findings of the studies carried out so far. Usually, when using fragments of this very long book in various publications, historians do not pay attention to the work itself and instead settle for referring to the main literature on the subject. The latter, however, does not provide an analysis of De aedificiis, but only brief descriptions, since its main interest are essential issues which make it possible to provide a comprehensive characteristics of Procopius’ diverse writings, and so his individual works are presented from this perspective.

Due to the fact that historical studies are behind time, when analysing individual fragments of De aedificiis it seems necessary to take into account, as far as possible, the significance of these partial findings for the comprehensive characteristics of the work. The version which has survived in manuscripts consists of six books.