March of Istria

[1] The settlement area of the ancient Histri tribes had been conquered by the Roman Empire in 178 BC and was incorporated into the northeastern Venetia et Histria region under Emperor Augustus.

Upon the Decline of the Roman Empire and the Migration Period, the Lombards under King Alboin from 568 onwards conquered Venetia, where they established the Duchy of Friuli, part of their Kingdom of Italy.

The Istrian peninsula remained under Byzantine (Eastern Roman) influence, while South Slavic tribes (Croatians and Slovenes) settled in the east and north.

As Pope Zachary expected no help from Constantinople, he forged an alliance with Pepin the Short, the powerful Mayor of the Palace of the Frankish kingdom north of the Alps, whom he legitimized as King of the Franks.

In the first decade of the 9th century, Istria was ruled by one Duke John, nominally according to its ancient Byzantine customs, but in fact as a Frankish vassal.

The German king Henry IV nominally assigned the remaining march to the Patriarchate of Aquileia, the margravial title and the Istrian territories were however retained by Carniola.

Aquileia regained Istria in 1209, when the Andechs margraves were banned due to alleged entanglement in the assassination of the German king, Frederick Barbarossa's son Philip of Swabia.

The patriarchs had ceased appointing margraves and had given the remaining interior of the peninsula into the direct control of their Vogt officials, the Counts of Görz.

Venetian Istria fell to the Habsburg monarchy (the Austrian Empire after 1804) according to the 1797 Treaty of Campo Formio but was subsequently seized by Napoleon in the 1805 Peace of Pressburg, forming part of the Kingdom of Italy.