Two main versions of the Chronicle of George the Monk contain two fairly different ac- counts on St. Arsenius and his activities at the court of Emperor Theodosius as tutor of the latter's sons Arcadius and Honorius. The priority of the version of Coislinianus 305 now hav- ing been firmly established, it is necessary to revise the hitherto prevailing view on the origin of these accounts. The most probable solution is that both George the Monk and Theodore the Studite a few decades earlier used one and the same lost source - a certain narration on St. Arsenios, apparently of Roman origin. The re-worker of the chronicle substantially modified the account by inserting additional details from the same narration and removing some of the existing material. The Narration BHG 167z derives in its primitive form directly from the sec- ond version of George the Monk, and not vice versa. The article offers a new edition of the account found in the original chronicle of George, emendated with the help of the 14th centu- ry Slavonic translation, which displays text of much higher quality than Coislinianus 305.