Prehistorically the Berner Oberland was crossed by hunters or traders, but the first known settlements were from the Roman era. The Romans settled along the river and the lakes. They used a number of alpine passes including; the Brünig, Susten (with a Roman mansio), Grimsel, Lötschen, Gemmi, Rawil, Sanetsch and the Col du Pillon.
During the High Middle Ages, a number of Berner Oberland villages grew around valley parish churches which were religious and cultural centers within each surrounding valley. During Middle Ages, the Berner Oberland first belonged to the Kingdom of Burgundy followed by the Dukes of Zähringen. After the extinction of the Zähringen line, the Berner Oberland was ruled by a number of local Barons (including Oberhofen, Strättligen, Brienz-Ringgenberg, Wädenswil, Weissenburg). For a time, some of the Walser barons (Raron, vom Turn) ruled portions of the Berner Oberland. The Saanen valley was ruled by the Counts of Gruyères. Portions of the alpine passes were held, until the 19th century, by the Bishop of Sion.
The expansionist policy of the city of Bern led them into the Berner Oberland. Through conquest, purchase, mortgage or marriage politics Bern was able to acquire the majority of the Berner Oberland from the indebted local barons between 1323 and 1400. Under Bernese control, the five valleys enjoyed extensive rights and far-reaching autonomy in the Bäuerten (farming cooperative municipalities) and Talverbänden (rural alpine communities). Throughout the Late Middle Ages, the Berner Oberland, as a whole or in part, revolted several times against Bernese authority. The Evil League (Böser Bund) in 1445 fought against Bernese military service and taxes following the Old Zürich War, in 1528 the Berner Oberland rose up in resistance to the Protestant Reformation and in 1641 Thun revolted.
During the Middle Ages, the settlement pattern in the Berner Oberland was somewhat consistent. A main settlement grew on the valley floor below an elevation near 1,100 m (3,600 ft). This main settlement had a market and often a castle or other fortifications. This market town was surrounded by scattered villages, hamlets and individual farm houses to an elevation of 1,600 m (5,200 ft). During the 14th-16th centuries, the Berner Oberland villages began extensive trading with the Bernese grain producing towns in the lowlands. This allowed the alpine villages to renounce self-sufficiency in grain and focus on raising cattle in the high alpine pastures and bringing them down into the valleys in the winter (transhumance). They then exported cattle over the passes into Italy and into the Bernese lowlands. Around 1500, in addition to the seven medieval markets, eleven new cattle markets opened to allow the Berner Oberland villagers to sell their cattle.
After the Napoleonic invasion of Switzerland in 1798, the old Bernese order was fractured and the Berner Oberland was separated from the canton of Bern, forming the canton of Oberland. Within this new canton, historic borders and traditional rights were not considered. As there had been no previous separatist feeling amongst the conservative population, there was little enthusiasm for the new order.
The 1801 Malmaison Constitution proposed reuniting the canton of Oberland with Bern, but it was not until the Act of Mediation, two years later, with the abolition of the Helvetic Republic and the partial restoration of the ancien régime, that the two cantons were reunited.
In 1729, Albrecht von Haller published the poem Die Alpen about his travels through the alpine regions. This combined with other reports and alpine paintings started the tourism industry in the Berner Oberland. By 1800 there were resorts on Lake Thun and Lake Brienz (especially at Interlaken between the two lakes). Shortly thereafter the resorts expanded into the alpine valleys (Lauterbrunnen, Grindelwald), and began attracting English guests. However, because of the widespread poverty of the 19th century many residents of the Simmen valley and the Interlaken district emigrated to North America, Germany or Russia.
In the late 19th century, new transportation links made it easier for people to travel into the valleys. The Bern-Lötschberg-Simplon railway opened in 1913 and became the largest privately owned railroad in Switzerland.
The collapse of the hotel industry during both world wars forced a diversification of the economy. After 1950 a new wave of hotel construction of hotels and holiday homes and apartments, led to a strong population growth.
Starting in the 1930s and increasingly after 1950 funiculars, cable cars and chair lifts opened up many of the high alpine villages for winter sports and tourism. Source: Wikipedia.