Battle Abbey was founded by William at the site of the battle. According to 12th-century sources, William made a vow to found the abbey, and the high altar of the church was placed at the site where Harold had died. More likely, the foundation was imposed on William by papal legates in 1070. The topography of the battlefield has been altered by subsequent construction work for the abbey, and the slope defended by the English is now much less steep than it was at the time of the battle; the top of the ridge has also been built up and levelled. After the Dissolution of the Monasteries, the abbey's lands passed to secular landowners, who used it as a residence or country house. In 1976 the estate was put up for sale and purchased by the government with the aid of some American donors who wished to honour the 200th anniversary of American independence. The battlefield and abbey grounds are currently owned and administered by English Heritage and are open to the public. The Bayeux Tapestry is an embroidered narrative of the events leading up to Hastings probably commissioned by Odo of Bayeux soon after the battle, perhaps to hang at the bishop's palace at Bayeux. In modern times annual reenactments of the Battle of Hastings have drawn thousands of participants and spectators to the site of the original battle.