Complex sentence: On 12 May 1264, Simon de Montfort forces occupied a hill known as'Offam Hill' outside Lewes, the royalist forces tried to storm the hill but ultimately were defeated by the barons'.
Split into simpler sentences: On 12 May 1264, Simon de Montfort's forces occupied a hill known as' Offam Hill'outside Lewes. Royalist forces tried to storm the hill but ultimately were defeated by the barons'.