The article analyses one of the stories given in the Chronicle of John of Nikiu (late 7th century AD), namely his story of the Persian king Cambyses (530–522 BC). The author shows that when John wrote it, he used a number of sources, of which only Josephus Flavius’ Antiquities of the Jews and the Old Testament, in particular the Book of Ezekiel, can be clearly recognized. It is difficult to identify exactly his other sources, however it is obvious that they were of Egyptian origin. It is likely that for his description of Cambyses’ conquest of Egypt John used three such sources that did not survive to the present time. These sources seem to have been part of the tradition that took form in Egypt not until the 3rd century AD (perhaps shortly after 451) and then became spread in this country.