In 799 A.D. the world turned upside down for the clergymen of the Saint Philbert monastery, located on the modern day island of Noirmoutier in France. Following the first attack, the monks retreated to the continent where they waited for a sign from God to decide on what to do next. The Archbishop of Tours, who at the time was the top official for the region, approved the construction of a satellite priory on Grand-Lieu lake, a place distant enough from the coast to avoid being sacked. It took nearly a decade before the monks returned to the island to assess the damage done to their monastery. With renewed approval from the archbishop, the monks rebuilt thinking the attack had been a singular event.
They were wrong.
For the next two decades, the Northmen attacked the island repeatedly. The monks decided to split their time between their two places of worship, spending their winters on the island and their summers on the continent to wait for the raiding season to pass. They carried out this commute until the early 830’s when, spurred by the ineptitude of the Carolinian Empire who were plunged in civil war, the Archbishop of Tours took it upon himself to ensure the safety of the clergy.
In 834 A.D. the church leadership funded the construction of a castrum on the site of the Saint Philbert monastery and hired a garrison of conscripted soldiers to defend it in summer. According to the firsthand account of an anonymous monk under the pen name of Ermentarius, the summer the castrum had been finished, the Northmen made their appearance. What the monks had not anticipated was the calibre of man who they were fated to face.
The warlord Hastein (click to read about Hastein) made his first incursion into the Bay of Biscay that summer with the hopes of finding riches described to him by his kin in Ireland. He landed on the island and found the new fortifications in place. Immediately, he set his men upon the wooden wall and within a day they managed to breach the defenses. With their conscripts dead or fleeing, the monks attempted to save themselves to no avail.
In the aftermath of the battle, the monks abandoned the island definitively. To their chagrin, the castrum they had build served as the perfect base for Hastein who used it to store his loot and launch raids across the region. The Annales D’Angoulême document, which recounts the sack of Nantes in 843 A.D., describes the island as a permanent base for the Northmen and later in 847 A.D. as the base from which the Vikings launched a mainland invasion of Brittany.
In their attempt to fend off the Northmen, the clergymen appear to have only encouraged them.