Battle Abbey was built by William the Conqueror after his victory at the battle of Hastings (October 14, 1066).One version states that William I had promised to build an abbey if he was victorious. Another version is that it was built to repent for the sin of bloodshed. Building the abbey at this site then would accomplish any or all of these things in addition to providing a memorial for those slain in the battle.
In February 1094 the Abbey church was consecrated. William I directed that the High Altar be placed on the spot that the defeated King Harold fell. Legend says that a fountain of blood appears there at times. This is pure legend as I have yet to find any first hand account of this event.
There are, however, accounts in the 1800's that ghost of a woman walked the grounds. Her identity has not been ascertained. The ghost of a monk has also been seen on the aptly named Monk's Walk. He is thought to be the ghost of a monk who cursed Sir Anthony Browne. Sir Anthony had received the monastery as a gift from Henry VIII during the dissolution. It was at this time that the church was basically destroyed. All that is left of the church today is an outline on the ground. Where the church's altar was, which marked where King Harold died, there is a plaque on the ground.
Sources for historical information:
The Abbeys and Priories of Medieval England by Colin Platt.
The Battle of Hastings Ed. Stephen Morillo