Empress Matilda's invasion finally began at the end of the summer of 1139. Baldwin de Redvers crossed over from Normandy to Wareham in August in an initial attempt to capture a port to receive Matilda's invading army, but Stephen's forces forced him to retreat into the south-west. The following month, the Empress was invited by her stepmother, Queen Adeliza, to land at Arundel instead, and on 30 September Robert of Gloucester and Matilda arrived in England with a force of 140 knights. Matilda stayed at Arundel Castle, while Robert marched north-west to Wallingford and Bristol, hoping to raise support for the rebellion and to link up with Miles of Gloucester, who took the opportunity to renounce his fealty to the King and declare for Matilda.