Alien priories were those in England who were dependant on usually French mother houses. During the Hundred Years War these priories were seen as a security risk. They also were a means of transferring much needed English money to France. A law was passed confiscating these priories. Many were transferred over to other religious orders.

In 1414 France was in the midst of a civil war between the Burgundians and the Armagnacs. While Charles VI, the French king, had joined the Armagnacs, Henry V, the English King, saw an opportunity to reclaim lost lands in France and came in on the side of the Burgundians. Henry's plan was to invade France but he needed a good reason. He gave the French king a list of demands including the French throne, the restoration of the Angevin empire and the hand of the French king's daughter in marriage. If the demands were not be met Henry would go to war. Henry could claim the French throne through a claim first made by his great-grandfather Edward III that started the Hundred Years War.||In August of 1415, invasion plans were completed and Henry's army met at Portchester Castle where they boarded ships to take them across the English Channel to France.

As negotiations were underway in France, England was preparing for the invasion of France.

Led by Richard Earl of Cambridge, Henry's cousin, a plot to assassinate the King and replace him with the Earl of March who was the true heir to the throne was hatched. The revolt brought together all the old enemies of Henry including Lord Scrope (Archbishop Scrope's nephew) and the Lollards. The Earl of March whose loyalties were with the king informed Henry of the plot the night before and the rebels were arrested. Several were executed.

Preparations for war were complete and Henry's army set sail from Southampton for the French coast.

Henry's army landed on the north bank of the Seine estuary near to the town of Harfleur (now part of Le Havre). Henry organised the siege of the town and waited for it to fall.

The town held out for five weeks in which time the English soldiers were starting to suffer from disease caught from their camps in the marshes. The people in the town were not doing much better and when it was clear that the town was not going to be rescued, the citizens surrendered. Henry treated the towns people with respect and let them leave.

Henry's plans for invading France had been dented by the time it took to capture Harfleur and the affect of disease on his men. He decided to move his men to Calais which was under English control.

Henry's plan was to get across the Somme at its estuary where it was relatively easy to cross but he received word that the crossing was being guarded by the French. Henry had no other choice but to follow the west bank of the Somme south into French territory to find a suitable crossing point. His men were short of food as Henry had told them to take only a few day's supplies expecting them to reach Calais. Henry finally found a crossing point that was unguarded and his army crossed the Somme.

The English army met the French army near the town of Agincourt. Although the English were outnumbered three to one, Henry used the local terrain to his advantage. The French cavalry were hit heavily by the English archers and French knights got bogged down in the wet fields. The French were defeated and Henry ordered that no prisoners should be taken apart from the extremely important knights who could be ransomed. The death toll amongst the French nobility was high.

After a few weeks recovering in Calais from their ordeal, Henry and the English army returned to England to a hero's welcome.

A French fleet laid siege to Harfleur, the French port captured by Henry V, and attempted to get it back. Harfleur was defended by Thomas Beaufort, the earl of Exeter.

An English fleet commanded by John Duke of Bedford attacked and defeated the French blockading the mouth of the Seine who were preventing supplies reaching the English held town of Harfleur. Bedford was the king's brother.

King Henry began his second French campaign when he and his large army landed at Trouville on the north coast of Normandy.

Once in France, King Henry appointed his brother the Duke of Clarence as Marshall of his army and together they advanced and laid siege to the city of Caen. Henry's attempt to storm and breach the walls failed, but his brother's attack on the other side of the walled city succeeded and the city fell to the English. It took several more days for the fortified castle within the city to be captured.

King Henry was not troubled by any Burgundian attempts to stop his progress and by the end of July had begun the siege of the important city of Rouen.

The city of Rouen in Normandy surrendered to the English King after a siege of seven months.

In the Treaty of Troyes King Charles VI of France agreed that after his death King Henry V of England and his heirs would become the rulers of France. It was also agreed that the French king's daughter, Catherine of Valois would marry Henry.

King Henry began the siege of the city of Meaux.

The French town of Meaux finally fell to the English besiegers. This being Henry's last great victory against the French.

Charles VI of France died and was buried in the Saint Denis Basilica. Henry VI of England was proclaimed king of France and John Duke of Bedford was appointed regent.