During the 17th century, Colmars-les-Alpes was on the frontier between France and Savoy. The town lies on the French side of the Col d'Allos pass, which was only a feasable invasion route for part of the year due to the climate. Colmars was strongly fortified in medieval times and its defences were improved by Franšois I in 1527.
These improvements consisted of bastions'with loopholes'for musketeers to fire through. Because there was little risk of artillery being brought over the pass, the walls of these bastions were only thin, about 80cm in thickness.
In 1690 war broke out between France and Savoy. That summer the Savoyards attacked over the Col d'Allos, laying siege to Colmars-les-Alpes. The town was able to hold out until the arrival of a contingent of French troops forced the besiegers to retreat back over the pass.
As a result the governor of Provence, Niquet, began to make improvements to the fortifications, modifying some of the medieval towers. In 1692, Vauban'reviewed the plans, but he was concerned about the possibility of an enemy bringing heavy artillery over the pass.
However, Niquet and others who were familiar with the Col d'Allos thought this was impossible and the Savoyards had abandoned a light gun when they retreated over the pass in 1690.
To enable the fortress to be defended against artillery, Vauban proposed the construction of some tower bastions'mounting guns. He also proposed two outlying forts or redoubts'to protect high ground that could be exploited by an attacker.
To the north of the town was the Fort de Savoie (also called Fort Saint-Martin or Fort Desaix). The fort is protected naturally by a steep cliff to the north and by the river to the west.
There is a large round tower on the south-west corner. The fort has its own barracks, cistern and kitchens, designed for a garrison of 150 men. When Vauban visited Colmars in 1700, he was disappointed with the Fort de Savoie. He proposed a bastioned front on the south side.
To the south of the town, was the Fort de France (also called Fort du Calvaire or Fort Soult). This small fort is a simple square redoubt with four embrasures on each side. The interior is divided in two by a thick wall to stop canonballs being fired into the fort.
Both the Fort de Savoie and the Fort de France were linked to the town's defences by a caponnier'(a covered path that allowed communication between the forts and the town).
The defences of Colmars itself are similar to those of Villefrance-de-Conflent, but with a distinct alpine character. As at Villefranche, there is a covered, loopholed parapet running along the top of the wall. The gates are somewhat unusual, retaining their medieval barbicans and protected by two towers. There are towers at intervals along the walls, but the defences are essentially medieval in form, with minor modifications to adapt them for firearms and artillery.
The defences of Colmars-les-Alpes itself are relatively well preserved, though a section of the wall in the south no longer exists. It is possible to walk along a large part of the walls (entry at the museum) for a small fee. The Fort de Savoie is open and can also be visited - the shop stocks a variety of fortification books, and the fort also contains a museum on fortification in Provence. The Fort de France is in good condition on the outside, but the inside is mostly ruined.
There is no train station at Colmars, so it is advisable to take a car unless there is a bus from Barcelonnette. The town is very pleasant, in some ways similar to Entrevaux in atmosphere, as well as in its adapted medieval fortifications.