The survival, as binding material, of a single folio written in Beneventan script and neumes provides evidence for the existence of the Ambrosian antiphoner prior to 1058 and the earliest diastematic source for several melodies. A certain confusion on the part of the Beneventan scribe suggests that the Ambrosian liturgy was not familiar to him, and from this we may infer that, in the eleventh century at least, it was not usual in his region. Since the purpose of the book to which the fragment belonged was not practical, we may speculate that the prompting for its production was a scholarly interest in the liturgy presumably practised by the Ostrogoth and Lombard rulers of the south from the sixth to the eighth century, former Arians whose forebears had been converted to orthodoxy while residing in Ambrosian territory.