Friulian Middle Ages began in 568 with the foundation of the Lombard duchy and ended in 1445 with the end of the patriarchal State. The meeting of the Aquileian Church with the Lombard duchy, which is to be considered the origin of Friuli, gave its best results throughout the eighth century, under dukes Pemmo, Ratchis, Anselm and the patriarchy of Callistus, who moved his see to Cividale in 737. The end of the Lombard reign and the passage to the Frankish dominium following king Charles’ victory at Pavia (774) can be interpreted as a mark of continuity from the cultural viewpoint. The personalities who date back to the first Carolingian age are Paul the Deacon and Paulinus of Aquileia, as well as the Frankish noblemen Henry, Cadalo, Eberhard who were appointed to rule over the March of Friuli. Their presence is above all connected with the strategic function that Friuli had as a border march and departure base for military campaigns to the East. The lack of a stable dynastic power in the region during the Carolingian age gave the chance to the progressive affirmation of the Church of Aquileia, which had already paved its way to a new Aquileian centrality with patriarch Paulinus II: the ecclesiastical and secular power of the patriarchs increased together with the accumulation of patrimonial endowments (mostly given by the sovereigns) and immunities. It was with the advent of the Saxon dynasty that a new impulse was given to the political and military role of the patriarchs who were chosen within families loyal to the sovereign. Patriarch Poppo (1019-1042) was personally familiar to Henry II of Saxony, to Conrad II the Salian of the house of Franconia and his son Henry III, who all largely favoured him. With Sigeard (1068-1077), former imperial chancellor, the process of establishment of the Aquileian ecclesiastical principality was accomplished: indeed, at the beginning of April 1077 emperor Henry IV gave Sigeard and the Aquileian Church the county of Friuli with all connected rights and privileges and juridical, military and fiscal authority over the other landlords of Friuli. The ‘patriarchal state’ lasted from 1077 to 1445: to better understand its developments, some historians have proposed a split between the age of Ghibelline patriarchs, from the eleventh to the half of the thirteenth century, and the age of Guelph patriarchs from the second half of the thirteenth century to the fall of the patriarchal state. The immediate reason for the Venetian military intervention, which ended up by their occupation of Udine and the whole Friuli, was the anti-Venetian alliance of patriarch Louis of Teck with emperor Sigismund; but deeper reasons were much more complex: internal struggles that tore the territory, the no-longer bearable insecurity of the communication routes, the games of international politics, the repercussions caused by the Western schism and last, but not least, the commercial, financial and strategic interests of Venice.