Saint-Omer

History and description

A town of Merovingian origin, Saint-Omer has been fortified since 900, when a castle and a market were installed around the collegial and surrounded by an urban wall of earth and wood. This urban wall was replaced by another, larger, around 1200. Initially in wood and earth, it was constructed from 1338 and equipped with towers. Following these reinforcements, the end product was a protective wall following an irregular route and with seventy towers, walls with arcades and battlements. Eight gates allowed access. From 1533, this urban wall was readjusted to the requirements of artillery with cannon balls: the irregularities were cancelled out, and eaves behind the west moat. The first bastion was constructed under Philippe II of Spain in 1559-1561. This was the bastion of Egmont, which replaced the medieval castle by enclosing it. In 1577, platforms for cannons were installed and the walls were lowered and remodelled. From 1611 to 1625, under the Archdukes Albert and Isabelle, governors of the Netherlands Spanish, multiple other bastions and ravelins completed the defences. Certain projects remained unrealised due to lack of funds, but what was created was sufficient to repel a French siege of seven weeks in 1638. The Spanish reinforced the defensive installation in 1666 by the construction of the fort Saint-Michel and new detached works in front of the western front. In 1677, during the war of Holland, Saint-Omer was besieged again by the French and taken by the brother of King Louis XIV.
From 1678, Vauban completed the ramparts of Saint-Omer. Under his direction, the engineers Robelin and Richerand transformed the bastion of Egmont and the medieval castle into an entrenched construction. The covered ways were adjusted and traverses were constructed. The flood defence system was improved by the creation of the crown of Maillebois to protect the dykes. All the moats surrounding the site were flooded.