Later campaigns
When the Treaty of Tours (which had established a truce between England and France) ended in 1449, Charles VII launched a campaign to retake Normandy in northern France. Bombardments by the Bureaus' artillery aided in the capture of Rouen (October 1449), Harfleur (December 1449), Honfleur (January 1450), and Fresnoy (January 1450). To ensure a continuous bombardment of English-held Cherbourg, the Bureaus placed their guns below the high water mark on the town's seaward side, leaving them submerged during high tide, and returning to resume the bombardment during low tide.
On 15 April 1450, a French force led by the Duke of Bourbon clashed with an English force sent to relieve the beleaguered region at the Battle of Formigny. The French initially attempted to charge the English position, but were driven back by English longbowmen. The Bureaus then advanced two cannons (likely two breechloading culverins), and barraged the English position. The barrage was effective, particularly since the cannons had a greater range than English longbows, but the French failed to provide protection for the cannons, and the English were able to charge and capture them. Cavalry reinforcements arrived later in the day to seal a decisive victory for the French, which paved the way for the capture of the remaining English strongholds in Normandy.
In 1451, the Bureaus joined the French invasion of Gascony, in southwestern France, and were instrumental in the recapture of several cities, including Bordeaux, which surrendered in June. Jean Bureau was appointed Mayor of Bordeaux in August 1451, but the local Gascon population revolted against the new leaders and invited the English to return. In October 1452, the Earl of Shrewsbury, Sir John Talbot, reoccupied Bordeaux with an English force of 3,000. Within a few months, he had regained control of much of the Gascony region.
The French launched their campaign to retake Gascony in the Spring of 1453. Bureau, now leading an army of about 7,000, laid siege to the town of Castillon, east of Bordeaux. He deployed 300 cannon in fortified field defenses on the town's perimeter. Remembering the loss of his cannons at Formigny, he attached a force of archers in the woods adjacent to his position to protect the cannons from capture. Talbot arrived with a relief force on 17 July, and routed a small advanced force of French archers. Mistakenly believing the French were retreating, he attacked the French camp, and his army was decimated by Bureau's cannon fire. Talbot's horse was hit by a cannonball, and he was killed by a French archer shortly after.
Bureau proceeded to Bordeaux, which he surrounded with 250 artillery pieces. After a 10-week siege, Bordeaux sent a delegation to Charles VII asking for terms of surrender. Bureau, confident in the positions of his batteries, told the king, "I promise you on my life that in a few days I shall have demolished the town." Hearing this statement, the delegation agreed to accept Charles' harsh terms, and control of the town was turned over to the French on 19 October 1453.
