Arlon (aʁlɔ̃; Arel ˈaːʀəl; Aarlen ˈaːrlə(n); Arel ˈaːʁəl; Årlon; Orolaunum) is a city and municipality of Wallonia located in and capital of the province of Luxembourg in the Ardennes, Belgium. With a population of just over 28,000, it is the smallest provincial capital in Belgium.
Arlon is also the capital of its cultural region: the Arelerland (Land of Arlon in Luxemburgish).
The municipality consists of the following districts: Arlon, Autelbas, Barnich, Bonnert, Guirsch, Heinsch, and Toernich. Other population centers include:
Autelhaut
Clairefontaine
Fouches
Frassem
Freylange
Hachy
Heckbous
Rosenberg
Sampont
Schoppach
Sesselich
Seymerich
Stehnen
Sterpenich
Stockem
Udange
Viville
Waltzing
Weyler
Wolberg
Before the Roman conquests of Gaul, the territory of Arlon and a vast area to the southeast were settled by the Treveri, a Celtic tribe. The local population adapted relatively easily to Roman culture. The number and quality of sculpted stones and monuments that have been unearthed in the area demonstrate that the vicus of Orolaunum quickly became a commercial and administrative centre of Roman civilization. The Germanic invasions of the 3rd century destroyed most of these early advances, despite the defensive walls that had been built on the Knipchen hill to protect the vicus.
During most of the Middle Ages, the population still used the earlier buildings such as the thermae. In 1060, Waleran I of Limburg, Count of Arlon, built a castle on the Knipchen hill in the centre of the town.
A dynasty of counts of Arlon began with Waleran I, Duke of Limburg. On the death of Duke Waleran III in 1226, Arlon passed to his son from the second marriage, Henry V the Fair, Count of Luxembourg, and became part of the county of Luxembourg. Thus, in the Tournament of Chauvency, his son Henry the Lion bore the title of Marquis of Arlon.
In the 13th century, the only women's Cistercian abbey known to date was built in Clairefontaine.
The Duchy of Luxembourg itself, of which Arlon was dependent, became part of the Burgundian Netherlands under Philip the Good in 1441.