The Dark Angel (original title Johannes Angelos) is a novel by Finnish author Mika Waltari about a hopeless love affair and the Fall of Constantinople.

On his way to Constantinople, he had passed through the Ottoman camp - and Mehmed had let him proceed, hoping that he would press his claim and ignite a civil war inside the besieged city.

[1] Scholar Panu Rajala [fi] visited Biblioteca Nazionale Marciana, which held both a copy and the original, and read from the checkout list that Mika Waltari was the fourth one to be allowed to examine the book, on 7 November 1952.

[1] Waltari abandoned an early draft, closer to his previous novels in structure, which was published posthumously in 1981 as Nuori Johannes  [fi].

[2] Time praised Waltari as an "anything but clumsy" novelist with his portraiture of the battle environment, and likened the fractures forming in Constantinople's walls to the growing division between Christians, leading to irreparable ruination.