The 1348 siege of Calais began before dawn on December 31, 1348 and ended later that morning. This siege was the result of a secret arrangement for Sir Geoffrey de Charney, a French knight, to purchase Calais from Sir Aymery de Pavia, the English-appointed Governor of Calais. Sir Geoffrey gathered a cavalry to take control of the town in December of that year, and King Edward III of England discovered the plot and brought an army from England and prevented the takeover.
The English took control of Calais following a siege in 1346. King Edward III appointed as Governor of Calais a Lombard whom he had known and trusted for many years, Sir Aymery de Pavia. In 1348, Aymery conspired with Sir Geoffrey de Charney, a French knight, to sell Calais to him for 20,000 crowns. When Edward discovered the plot, he summoned Aymery to England and confronted him. Aymery begged for leniency and informed the king that no money had yet been delivered and that Calais was still under his control. Edward commanded Aymery to keep his bargain and inform the king when the deal would be done.
In late December 1348, Sir Geoffrey gathered 500 lancers to take control of the castle and town of Calais. Before dawn on the 31 December, he led this army across the bridge of Nieullet and sent two squires to confirm the plan with Sir Aymery. Receiving that confirmation, Sir Geoffrey sent twelve knights and 100 men at arms to take control of the castle, along with Sir Odoart de Renty to deliver to Sir Aymery the agreed upon 20,000 crowns. Receiving the bag of gold, Sir Aymery locked it away, lowered the castle's drawbridge so the French could enter, and led the French company to the castle's tower. When he unbolted the tower door, the French company found King Edward with 200 lancers waiting in ambush. Seeing that they were outmatched, the French company surrendered with few casualties and were confined in the tower.
The English cavalry rode out from the castle led by Edward and his son under the banner of Sir Walter Manny. Also in the English expedition were Earl Suffolk, Lord Stafford, Lord John Mountecute, Lord John Beauchamp, Lord Berkeley, and Lord de la Waae. King Edward sent a detachment of three cavalry units and six hundred archers to meet the French reinforcements at the bridge of Nieullet, where they met an army led by Lord Moreau de Fiennes and Lord Crequi, while crossbowmen from Saint-Omer and Aire were stationed in front of the bridge. The forces met around dawn and ended with an English victory, though the French took several English prisoners. Meanwhile, outside the walls of Calais, King Edward met Sir Eustace de Ribeaumont in single combat, but their fight was interrupted by the advance of the warring armies.