It came under Frankish rule during the reign of Charlemagne, when his son Carloman conquered the peninsula in 789, and it was incorporated into the Carolingian March of Friuli.

In 952 King Otto I of Germany ceded Istria together with the vast March of Verona and Aquileia to the Dukes of Bavaria.

In 1208/09 it fell to the Patriarchs of Aquileia, while large parts of the estates were held by the comital House of Gorizia.

Starting in 1267 the Republic of Venice gradually annexed the Istrian coast, also aided by the strong presence of the native Romance-speaking communities; the region regained its overseas ties which were loosened by the barbarian invasions.

The coastal area somewhat reflowered, but the Venetian government's enmity toward Austria and the Ottoman Empire limited relations with the hinterland.

After Napoleon's triumph in Padania, the Treaty of Campo Formio in 1797 gave most of the Venetian Republic and all of the peninsula to the Habsburgs.

As a consequence, between 1945 and 1954, an estimated 350,000 ethnic Italians left the Slovenian Istria in the so-called Istrian–Dalmatian exodus, together with several thousand Slovenes.

Between 1947 and 1954, Slovenian Istria was divided between the Federal People's Republic of Yugoslavia and the Free Territory of Trieste.

A significant portion of the rural population moved to the coastal towns, which remained semi-deserted after the Istrian–Dalmatian exodus.

The neighboring town of Portorož is a popular modern tourist resort, offering entertainment in gambling tourism.

[3] In the rest of Slovenian Istria, comprising most of its rural area, only Slovene is recognized as official language.

According to the 2002 census, Slovene is spoken as the first language by 70.2% of the inhabitants of Slovenian Istria, Italian by 3.3%, and various forms of Serbo-Croatian, dominated by Croatian, by 16% of the population.

Italian may be used in the municipal assemblies of Koper, Izola and Piran, although in practice almost all discussions are carried out in Slovene.

In the urban areas, a hybrid regional version of Slovene is spoken, which is phonetically very different from the rural dialects.

It developed after World War Two, when new settlers from all Slovenia (many of whom from Slovenian Styria) moved into the towns, left by the Istrian Italians.