Here is a sample of Beneventan Chant from Youtube: Otin to Stauron - O Quando in Cruce, sung by Ensemble Organum in Greek and Latin, from their album, Chants de la Cathédrale de Benevento: Semaine Sainte & Pâque.
What is interesting is that three bilingual (Greek and Latin) antiphons, of this is but one, were sung in Benevento and some other Italian centres as part of the Adoration of the Cross service in Holy Week. Some of these chants seem to have Eastern origins: this particular sample for instance, found in sources from places such as Benevento and Ravenna, is actually a version of a Byzantine troparion which can be followed back to the rite of Jerusalem in the 7th century. Its presence in Ravenna should mean that it was already used in the liturgy there before the fall of the Exarchate of Ravenna to the Lombards in 752.