Constantinople, now known as Istanbul, is one of the most important cities on the border between Europe and Asia, which has witnessed many events and catastrophes throughout history and has been destroyed and rebuilt many times. In the authoritative historical books, there are detailed materials about this city, which in this article are to be mentioned briefly, three treatises will be introduced as well. The subject of these treatises, according to the titles of the two versions, is the mention of the history of Constantinople and Hagia Sophia and the mention of the history of Hagia Sophia. All three treatises have similar contents, narrating a story about the kingdom of Ostoniano, one of the sons of Constantine, and the story of building a church called Hagia Sophia during his reign.
Each of the authors of these treatises has used a different source; The author of Ketab-e Zekr-e Qal’e-ye Qostantiniye va Bana’e Ayasofyat  f’l Tavarikh, Ahmad ibn Ahmad al-Monshi al-Jilani, rewrote it from "the treatise on the preparation of the foundation of the high building of the Hagia Sophia, which was translated from Roman into Persian” in order to be acceptable to common sense and direct mind of everyone. The author of the history of Hagia Sophia, Darvish Shams, translated the book directly from Roman into Persian. The author of Tarikh e Fath-e Qostantaniye  (the history of the conquest of Constantinople), in response to Azizi's request, translates a book, which had been translated from Roman into Turkish, into Dari Persian.
However, due to the high similarity of these three versions, in terms of volume and content, it was difficult to choose one and prefer it to the other. With all this, the written version of Monshi Gilani was selected due to its linguistic and literary features and was quoted as an example at the end of the article.