With Henry's support, he rapidly began to accumulate lands and possessions. Following the battle of Tinchebray in 1106, Henry confiscated the County of Mortain from William, Count of Mortain, and the Honour of Eye, a large lordship previously owned by Robert Malet. In 1113, Stephen was granted both the title and the honour, although without the lands previously held by William in England. The gift of the Honour of Lancaster also followed after it was confiscated by Henry from Roger the Poitevin. Stephen was also given lands in Alençon in southern Normandy by Henry, but the local Normans rebelled, seeking assistance from Fulk IV, Count of Anjou. Stephen and his older brother Theobald were comprehensively beaten in the subsequent campaign, which culminated in the battle of Alençon, and the territories were not recovered. Finally, the King arranged for Stephen to marry Matilda in 1125, the daughter and only heiress of the Count of Boulogne, who owned both the important continental port of Boulogne and vast estates in the north-west and south-east of England. In 1127, William Clito, a potential claimant to the English throne, seemed likely to become the Count of Flanders; Stephen was sent by the King on a mission to prevent this, and in the aftermath of his successful election, William Clito attacked Stephen's lands in neighbouring Boulogne in retaliation. Eventually a truce was declared, and William Clito died the following year. In 1120, the English political landscape changed dramatically. Three hundred passengers embarked on the "White Ship" to travel from Barfleur in Normandy to England, including the heir to the throne, William Adelin, and many other senior nobles. Stephen had intended to sail on the same ship but changed his mind at the last moment and got off to await another vessel, either out of concern for overcrowding on board the ship, or because he was suffering from diarrhea. The ship foundered en route, and all but two of the passengers died, including William Adelin. With Adelin dead, the inheritance to the English throne was thrown into doubt. Rules of succession in western Europe at the time were uncertain; in some parts of France, male primogeniture, in which the eldest son would inherit a title, was becoming more popular. It was also traditional for the King of France to crown his successor whilst he himself was still alive, making the intended line of succession relatively clear, but this was not the case in England.