Olivers Battery is a large Medieval earthwork motte and baileys fortress. The sub-rectangular enclosure overlooks the River Loddon and was possibly the site of a Saxon Monastic House called the King's Horse Croft. An east to west bank divides the bailey into two wards but the western half of this bank is ploughed out. Standing at the bottom north-west corner of this quite steeply sloping castle, is a motte which again has been reduced by ploughing. The bailey is encased by a wide ditch to the east and by a bank and ditch to the south but to the north and west there is only a fall in ground level, with no visible ditch. The castle may be the predecessor to or a siege-castle associated with, Basing House. 6 miles east is Odiham Castle.