The architecture of Switzerland was influenced by its location astride major trade routes, along with diverse architectural traditions of the four national languages. Romans and later Italians brought their monumental and vernacular architecture north over the Alps, meeting the Germanic and German styles coming south and French influences coming east. Additionally, Swiss mercenary service brought architectural elements from other lands back to Switzerland. All the major styles including ancient Roman, Romanesque, Gothic, Renaissance, Baroque, Neoclassical, Art Nouveau, Modern architecture and Post Modern are well represented throughout the country. The founding of the Congrès International d'Architecture Moderne in La Sarraz and the work of Swiss-born modern architects such as Le Corbusier helped spread Modern architecture throughout the world.
The relative isolation of villages in the Alpine foothills, the Alps and the Jura mountains as well as different languages led to great diversity in the vernacular style. Due to differing traditions, climate and building materials, villages in each region are distinctly different. The Swiss chalet style, which was popular in the 19th century represents only one of a number of traditional designs. Today, due to historic preservation laws and tourism, large and small communities have retained many of their historic core buildings. Since 1972 the Swiss Heritage Society has awarded the Wakker Prize to encourage communities to preserve their architectural heritage.
Ancient architecture
Some of the earliest known buildings in Switzerland were prehistoric stilt houses which were built by the Pfyn, Horgen, Cortaillod and La Tène cultures between 4000 and 500 BC. A number of these early buildings have been rebuilt near the sites where the ruins were discovered.
Following the defeat of the Helvetii at the Battle of Bibracte of 58 BC, over the next decades much of Switzerland was incorporated into the Roman Empire. The principal Roman settlements in Switzerland were the cities of Iulia Equestris (Nyon), Aventicum (Avenches), Augusta Raurica (Augst) and Vindonissa (Windisch). Evidence has also been found of almost twenty Roman villages (vici) established in the 1st to 3rd century AD, as well as hundreds of villas of varying sizes built in the western and central part of the Swiss Plateau. The Legio XIII Gemina, was based in the permanent camp of Vindonissa (Windisch) and Aventicum (Avenches) was the capital of the Helvetii.
Under pressure from internal and external forces, the Roman Army retreated and Switzerland became a border province in the 4th century. Nyon and Augusta Raurica were permanently abandoned during the 4th century, the stones of their ruins serving to fortify Geneva and Basel. Aventicum never recovered from its pillages: Ammianus Marcellinus noted in around 360 that "the city was once very illustrious, as its half-ruined buildings attest."
There are a number of excavated or rebuilt Roman sites in Switzerland. Some of the ruins of Roman settlements were later incorporated into houses, churches and city walls. All four of the major Roman cities have some relics of the Roman era. Augusta Raurica has parts of the amphitheater, aqueduct, the main forum and a theater. At Avenches the eastern gates and a tower, a thermal bath, the 16,000 seat amphitheater and temple ruins are still visible. At Nyon, the Roman ruins were lost until their rediscovery in the 18th century, which included the amphitheater and basilica. At Windisch the legionaries camp, an amphitheater and an aqueduct are all visible.
Ancient indigenous architecture includes rock shelters called "splüi", grotti and other anonymous architecture using rock.
Pre-Romanesque
The Pre-Romanesque period is considered to stretch from the emergence of the Merovingian kingdom in about 500 to the beginning of the 11th century Romanesque period, though there is considerable overlap. During the early centuries of this period, the area that would become Switzerland was sparsely populated and almost nothing remains of any buildings from the period between 500 and the late 8th century. During the Carolingian Renaissance of the 8th and 9th centuries, many new monasteries and churches sprung up across Western Europe. Carolingian architecture borrowed heavily from Early Christian and Byzantine architecture and helped lead to the Romanesque style in the following centuries. To begin expanding their power into the deep forests and isolated mountain valleys, the Carolingian kings established several monasteries in Switzerland.