A poem composed in response to the Synod of Mantua (6th of June, 827), arguing that Aquileia, the old metropolitan see of the ecclesiastical province Venetia et Histria, was so thoroughly destroyed by barbarians (Attila, the Avars, Lombards and Goths) that it was never rebuilt; thus, the metropolitan see transferred to "the Venetians" and Aquileia was demoted to a status of a mere parish.
Pope Leo IV writes to Victor, the patriarch of Grado, conferring upon him the pallium.
Emperor Louis II assumes under his protection the monastery of St. Michael in Diliano and its abbot Felmo, bestowing upon the monastery immunities and the right of free election of its abbots.
Emperor Louis II confirms the charter of Lothar I to the Patriarchate of Aquileia regarding the dispute with the Patriarchate of Grado that was settled at the Synod of Mantua in 827 (doc. 827_SM): the patriarchs of Aquileia are to enjoy the metropolitan jurisdiction over all the Istrian bishoprics.
Emperor Louis II confirms to St. Michael's monastery in Diliano and abbot Felmo the right to have two lay advocates - the brothers Petronasius and Talasius - to defend their rights.
Pope Benedict III writes to Vitalis, the patriarch of Grado, conferring upon him the pallium.