Before the Conquest of Gaul by the Romans, the land of Arlon was a vast territory where were living the tribe of the Treveri. The Treveri were a Gaulish tribe with Celtic and Germanic origins.
The territory of the Treveri covered the space between The Arduenna Silva (The forest of the Ardennes) and The Rhenus (The River Rhine). At present days, this territory would be nearly equivalent to the Province of Luxembourg, as well as the western part of the Grand-Duchy of Luxembourg.
After the Roman colonization, most of the Gaul’s tribes slowly adapted to the Roman culture.
After the fall of the Roman Empire, between the Antiquity and the Middle Age, Arlon was subjected to Merovingian influence.
During the Middle Age, a castle was constructed on the Knipchen hill. In the 13th century, the only cistercian female abbey was built in Clairefontaine.
The Duchy of Luxembourg, from which Arlon was dependent, became in 1441 part of the Netherlands Burgundians under the reign of Philippe the Good.
In 1588, Francois I of Lorraine, the 2nd Duke of Guise and his troops, on their way back from Thionville (France) ransacked, demolished and burned down the city and its walls. Almost half of the city was destroyed including the castle of the counts of Arlon. The monks Capuchin arrived in Arlon in 1621 and built their monastery on the ruins of the castle of the Counts. By 1681, the French troops added a fortification wall to the former monastery, converting it into a fortress according to the plans of the French military architect Vauban.
By the treaty of Utrecht in 1713, the Southern Spanish Netherlands became the Austrian Netherlands.
In 1785, due to a fire badly controlled in the monastery of the Carmelites, and also because of the strong wind, a big fire spread through the city and destroyed numerous accommodations amongst which 243 houses.
Between 1793 and 1794, the French troops delivered battle to the Austrians in Arlon.
The French were victorious at the end of these battles and occupied the city. They dispelled the monks and used the nunnery as hospital. After the battle of Waterloo, Arlon's history was linked to Belgium.
By 1839, Arlon was confirmed as the administrative capital of the Province of Luxembourg.
Today, the region of Arlon is spreading itself in terms of residential and commercial zones, notably thanks to its border situation with the Grand Duchy of Luxembourg. This interesting geographical situation brings more and more cross-border workers to move and settle in the region, for instance people coming from the French Ardennes, and also people moving in from the other Belgian provinces.