Paul the Deacon (c. 720s – 13 April in 796, 797, 798, or 799 AD), also known as Paulus Diaconus, Warnefridus, Barnefridus, or Winfridus, and sometimes suffixed Cassinensis (i.e. "of Monte Cassino"), was a Benedictine monk, scribe, and historian of the Lombards.

During an invasion by the Avars, Leupichis's five sons were carried away to Pannonia, but one of them, his namesake, returned to Italy and restored the ruined fortunes of his house.

[2] Thanks to the possible noble status of his family, Paul received an exceptionally good education, probably at the court of the Lombard king Ratchis in Pavia, learning the rudiments of Greek from a teacher named Flavian.

After Desiderius's daughter Adelperga had married Arichis II, duke of Benevento, Paul, at her request, wrote his continuation of Eutropius's Summary of Roman History (Latin: Breviarium Historiae Romanae).

It covers the history of the Langobards from their legendary origins in the north (in "Scadinavia") and their subsequent migrations—notably to Italy in 568–69—to the death of King Liutprand in 744.

He is said to have advised Adelperga to read Eutropius; she did, but complained that this pagan writer said nothing about ecclesiastical affairs and stopped with the accession of the Emperor Valens in 364.

This work, which was very popular during the Middle Ages, has value for its early historical presentation of the end of the Roman Empire in Western Europe.

[4] Neff denied, however, that Paul had written the most famous poem in the collection, the hymn to St. John the Baptist Ut queant laxis, which Guido of Arezzo set to a melody that had previously been used for Horace's Ode 4.11.

Paul also wrote an epitome, which has survived, of Sextus Pompeius Festus's De verborum significatu, which he dedicated to Charlemagne.

Paul also composed two important homilies In Assumptione, in the second of which, unlike Ambrose Autpert, he admits the possibility of Mary's bodily assumption into heaven.