The Patria del Friuli (, ) was the territory under the temporal rule of the Patriarch of Aquileia and one of the ecclesiastical states of the Holy Roman Empire. In 1420, the Republic of Venice acquired it, but it continued to be ruled for some time under its own laws and customs.
Foundation
The former Duchy of Friuli in the Italian Kingdom of the Lombards had been conquered by Charlemagne in 774 and incorporated as a march of the Carolingian Empire. When in 952 King Otto I of Germany invaded Italy, he added the Friulian territory to the March of Verona, ruled by the Dukes of Bavaria, from 976 by the Dukes of Carinthia.
During the Investiture Controversy of 1077, King Henry IV of Germany deposed the Veronese margrave Duke Berthold II of Carinthia, as he had sided with antiking Rudolf of Rheinfelden. On 3 April 1077 at Pavia Henry, on his way back from the Walk to Canossa, vested Patriarch Sieghard of Beilstein with immediate comital rights in the Friulian lands of Verona, raising him to the status of a Prince-Bishop. The remaining margraviate passed with the Carinthian duchy to Henry's vassal Liutold of Eppenstein.
Sieghard in turn safely conducted the king across the Alps. Back in Germany, King Henry in addition nominally assigned the suzerainty over the marches of Carniola and Istria to the patriarchs as ecclesiastical Princes of the Holy Roman Empire. The act, traditionally regarded as the birth of the ecclesiastical state of Aquileia, led to a long-running conflict with the rivaling margraves from the Carinthian House of Sponheim and the Andechs dukes of Merania.
Expansion
The Patriarchate subsequently extended its political control in the area: regions under Aquileian control in the following centuries included the Friulian lands up to Cadore, the city of Trieste and the central parts of the Istrian peninsula. At its maximum height, the Patriarchate of Aquileia was one of the largest states in Italy. Noblemen from the Patriarchate were participants in the Crusades. In 1186 Patriarch Godfrey crowned Frederick Barbarossa's son, Henry VI, as King of Italy: in retaliation, Pope Urban III deposed him.
From 1127 the vogts at Gorizia from the Meinhardiner dynasty emerged from Aquileia, calling themselves Counts of Görz. Their autonomy was strengthened, when they inherited the Imperial County of Tyrol in 1253 and were elevated to Princes of the Holy Roman Empire by Emperor Charles IV in 1365.
In the early 13th century, particularly under Volchero (1204–1218) and Berthold (1218–1251), the Patriarchate had a flourishing economy and cultural life, supported by a good road network. Damaged by earthquakes and other calamities, and reduced to a few hundred inhabitants, Aquileia was nearly abandoned in the 14th century. The capital of the state was moved first to Cividale and then, from 1238, to Udine in central Friuli, which had been a favourite residence of the patriarch since the 13th century and soon became a large city.
Rivalry with Venice
The patriarchs had regained the rule of the Istrian march from the Dukes of Merania in 1209. However, they had to cope with the rising naval power of the Republic of Venice, which in the late 13th century had occupied the western Istrian coast from Capodistria (Koper) down to Rovigno (Rovinj). In 1291 a peace was made in Treviso, whereupon the western coast of the peninsula fell to Venice. In the late century the patriarchate had to face the increasing rivalry with Venice, as well as the inner strifes between its vassals, and also became entangled in the endless wars between Guelphs and Ghibellines. In 1331 Venice also incorporated Pola (Pula) in the south. A certain recovery occurred during the rule of Bertrand (1334–1350), a successful administrator and military leader. He was killed in 1350 in a plot, at the age of ninety.
The Counts of Görz had retained some interior Istrian lands around Pazin (Mitterburg), which they bequeathed to the Austrian House of Habsburg in 1374. In view of the Venetian threat, the city of Trieste submitted to the Habsburgs in 1382.
Since the transfer of the patriarchal residence to Udine, the Venetians had never lived in peace with the Patriarchate, of whose Imperial favour and tendencies they were jealous. From about 1400, Venice under the Doge Michele Steno and his successor Tommaso Mocenigo began to enlarge its dogado by occupying the Aquileia hinterlands. At the same time, the Patriarchate suffered internal conflict between the citizens of Cividale and Udine.