She had an older half-sister Cecily Bonville from her mother's first marriage to William Bonville, 6th Baron Harington who was executed by the command of Queen Margaret of Anjou after the Battle of Wakefield where he fought on the side of the Yorkists.
In the aftermath of the 1461 Battle of Towton remnants of the Lancastrian forces fleeing the victorious Yorkists were forced to try to cross the Cock Beck, having already disposed of most of their arms.
In February 1461 the final skirmishes of the Second Battle of St Albans took place in and around Sandridge as the Earl of Warwick, for the Yorkists, retreated towards Nomansland.