The Aosta Valley is a mountainous semi-autonomous region in northwestern Italy. It is bordered by Rhône-Alpes, France to the west, Valais, Switzerland to the north and the region of Piedmont to the south and east.
Covering an area of and with a population of about 128,000 it is the smallest, least populous, and least densely populated region of Italy. It is the only Italian region which has no provinces (the province of Aosta was dissolved in 1945). Provincial administrative functions are provided by the regional government. The region is divided into 74 comuni (communes).
Italian and French are the official languages, though much of the native population also speak Valdôtain, a dialect of Arpitan, as their home language. In 2001, 96.01% of the Valdostan population reported knowing Italian, 75.41% French, 55.77% Arpitan, and 50.53% all of them.
The first inhabitants of the Aosta Valley were Celts and Ligures, whose language heritage remains in some local placenames. Rome conquered the region from the local Salassi around 25 BC and founded Augusta Prætoria Salassorum (modern-day Aosta) to secure the strategic mountain passes, and they went on to build bridges and roads through the mountains. Thus, the name Valle d'Aosta literally means "Valley of Augustus". After the Romans, the valley preserved traditions of autonomy, reinforced by its geographical isolation, though it was loosely held in turns by the Goths and then by the Burgundians in the 5th century, followed by the Franks, who overran the Burgundian kingdom in 534. It was also ruled by the Byzantines between 553 and 563 and then by the Lombards between 568 and 575 before the Franks finally conquered the area. At the division among the heirs of Charlemagne in 870, the Aosta Valley formed part of the Lotharingian Kingdom of Italy. In a second partition a decade later, it formed part of the Kingdom of Upper Burgundy, which was joined to the Kingdom of Arles — all with few corresponding changes in the population of the virtually independent fiefs in the Aosta Valley.
In 1031-1032 Humbert I of Savoy, the founder of the House of Savoy, received the title Count of Aosta from Emperor Conrad II of the Franconian line and built himself a commanding fortification at Bard. Saint Anselm of Canterbury was born in Aosta in 1033 or 1034. The region was divided among strongly fortified castles, and in 1191 Thomas I of Savoy found it necessary to grant to the communes a Charte des franchises ("Charter of Liberties") that preserved autonomy — rights that were fiercely defended until 1770, when they were revoked in order to tie Aosta more closely to Piedmont, but which were again demanded during post-Napoleonic times. The Aosta Valley was the first government authority to adopt Modern French as official language in 1536, three years before France itself. In the mid-13th century Emperor Frederick II made the County of Aosta a duchy (see Duke of Aosta), and its arms charged with a lion rampant were carried in the Savoy arms until the reunification of Italy in 1870. During the Middle Ages the region remained strongly feudal, and castles, such as those of the Challant family in the Valley of Gressoney, still dot the landscape. In the 12th and 13th centuries, German-speaking Walser communities were established in the Gressoney, and some communes retain their separate Walser identity even today.
The region remained part of Savoy lands, with the exceptions of French occupations from 1539 to 1563, later in 1691, then between 1704 and 1706. As part of the Kingdom of Sardinia it joined the new Kingdom of Italy in 1861. It was also ruled by the First French Empire between 1800 and 1814. During French rule, it was part of Aoste arrondissement in Doire department.
Under Mussolini, a forced programme of Italianization, including the translation of all toponyms into Italian and population transfers of Italian-speaking workers from the rest of Italy into Aosta, fostered movements towards separatism. Many Valdostans chose to emigrate to France and Switzerland (where Valdostan communities are still present).