Vol. 1: A seculo VI usque ad 803

Cassiodorus, as praetorian prefect, remits the collection of tax on wine and corn to the citizens of Concordia, Aquileia and Forum Iulii (Cividale del Friuli) due to a meager harvest; instead, he instructs his tax collector Paul to procure the necessary quantity of wine from Istrians who enjoyed a particularly abundant harvest.

Cassiodorus, as praetorian prefect, informs the provincials of Istria that a part of their due tax will be commuted in kind.

Cassiodorus, as praetorian prefect, sends Lawrence to Istria to examine the harvests and prepare a report of the yields in order for the taxes to be determined.

Cassiodorus, as praetorian prefect, orders the tribunes of the coast to be prepared to transfer the victuals from Istria to Ravenna by sea.

In the midst of the war between the Roman Empire under Emperor Justinian I and the Ostrogoths in Italy, the Roman general Belisarius plans the siege of the Ostrogothic capital Ravenna; The Po valley is blocked as Belisarius commands Vitalius, magister militum per Illyricum, to depart with his army from Dalmatia and subject the Ostrogothic towns of regio Venetia; traditionally taken as marking the Byzantine conquest of Ostrogothic Istria and the beginning of the centuries-long rule of the Eastern Roman Empire in Istria (narrative accounts from Procopius of Cesearea's History of the Wars).

Euphrasius, the bishop of Poreč, regulates the relations between the Bishopric and the Chapter and prescribes various taxes, including the tithe and the church quartese (a quarter of a tithe) owed by the inhabitants of Poreč and the retainers of church property (forgery composed in the second half of the 12^th, or the first half of the 13^th century).

Belisarius and Vitalius, the generals of Emperor Justinian I's army, draft new soldiers across Thrace and Illyricum as they prepare for a new assault against the Ostrogoths in Italy; they stop in Pula to regroup before sailing to Ravenna to engage the enemies (narrative accounts from Procopius' History of the Wars).

Emperor Justinian I has Pope Vigilius I consecrate Maximian, a deacon from Pula, as the new bishop of Ravenna; once installed as bishop, Maximian embarks on several architectural projects, including the building of the Santa Maria Formosa church in Pula (narrative accounts from the Life of Saint Maximian written by Agnellus of Ravenna in his Book of the Pontiffs of the Church of Ravenna).

Maximian, the bishop of Ravenna, endows the monastery of St. Andrew and the church of St. Mary in Pula.

Emperor Justinian I appoints his cousin Germanus as the commander-in-chief of his army fighting against King Totila in Italy; the promise of a renewed war effort against the Ostrogoths under a famous military commander encourages men across the region to rally under imperial banner as they journey to Istria, awaiting the arrival of Germanus (narrative accounts from Procopius of Cesearea's History of the Wars).

Emperor Justinian I issues a pragmatic sanction regulating the administration of the newly conquered Italy (the so-called sanctio pragmatica pro petitione Vigilii or epitome constitutionum Iustiniani de reformanda Italia).

Pope Pelagius I writes to patrician John regarding the detrimental consequences of the schism within the Church (the so-called Three Chapters Controversy), especially concerning the recent election of a schismatic patriarch of Aquileia, urging the Byzantine official not to recognize their authority as they had not been canonically elected.

Pope Pelagius I writes to patrician Valerian, beseeching him to repress the schismatics and support the quest to restore union to the Church.

Pope Pelagius I writes to a patrician John on the detrimental effects of the schism in the Church (the so-called Three Chapters Controversy), singling out Bishop Euphrasius as a particularly depraved schismatic and advising the patrician to repress the schismatics in the province of Aquileia (that is, the region Venetia et Histria).

Pope Pelagius I writes to patrician Valerian, urging him to take action against the schismatic bishops in the ecclesiastical provinces of Milan and Aquileia and support the papal quest to bring back unity to the Church.

Pope Pelagius I writes to patrician Narses, beseeching him to take action against the schismatic bishops, namely the bishop of Fossombrone and the bishops of Liguria, Venetia and Istria.

Pope Pelagius I writes to Charles, the magister militum, regarding the Schism of the Three Chapters and the schismatic bishops.

A poem composed by Venantius Fortunatus to a Vitalis, a bishop of Ravenna, traditionally identified as Maximian of Ravenna, but also as bishop Vitalis of Milan, bishop Vitalis of Altino, or even an eponymous, otherwise undocumented bishop of Pula.

Venantius Fortunatus composes a poem in celebration of the construction of the church of St. Andrew, built by a Vitalis, the bishop of Ravenna (most probably a laudatory nickname for Bishop Maximian).

Lombards under King Alboin invade Italy and conquer Friuli; Gisulf I, Alboin's nephew, is made the ruler (duke) of Friuli; Paulinus, the incumbent patriarch of Aquileia, flees from Aquileia due to the invasion and finds shelter in Grado where he hides the treasury of his Church as well (narrative account from Paul the Deacon's History of the Lombards).

Pope Benedict I officially sanctions the transfer of the episcopal see from Aquileia to Grado; 11th-century forgery included in the Chronicle of Grado.

Pope Pelagius II confirms Grado as the new metropolitan see of the ecclesiastical province of Venetia et Histria (11^th-century forgery).

The acts of the synod of Grado, heavily interpolated by later falsifications, by which the bishops of the ecclesiastical province of Aquileia remain faithful to the Catholic creed as decreed by the Ecumenical Councils of Chalcedon (451), Ephesus (431), Constantinople I (381) and Nicaea (325), refusing to denounce the Three Chapters condemned by the Second Ecumenical Council of Constantinople (552).

Gogo, the majordomo of King Childebert II, writes to Grasulf, the Lombard duke of Friuli, proposing an alliance with the Franks, the Papacy, and the Byzantine Empire against their common foes (presumably the Avars and the Slavs, but possibly even the Lombards).