Immunity from prosecution, secured by placing oneself in a sacred place. Those churches which offered sanctuary had a knocker on the main door and the sanctuary seeker had only to touch it to be safe. Some of these knockers were rather elaborate, e.g. Durham Cathedral, while others were plain rings. At Durham, the seeker of sanctuary struck the great knocker, the door was opened and the Galilee Tower bell was rung. The malefactor then made full confession in front of witnesses of probity. At Westminster, there is today a portion of the abbey precincts still known as the Sanctuary.
The idea of sanctuary is found for the first time in 600 in the laws of Aethelberht. For all its apparent sanctity, there are many records of sanctuary being broken. In the register of the bishop of Lincoln, Oliver Sutton (1280-99), one can find penalties imposed upon a man for seriously injuring another he dragged forcibly from sanctuary. The penalties were for the injury - the use of force in a sacred place - and he was obliged both to pay doctor's fees and visit the injured man in prison and try to help him. However, the penalty for breaking sanctuary violently could be death. Taking a person from sanctuary was something for which there could be no compensation in the old English way of things. In certain circumstances a person could be removed on condition the death penalty would not be imposed. In English law, the sanctuary or asylum seeker was required either to submit to a trial or to take an oath to leave the kingdom; to return required the king's permission. The person in sanctuary was given 40 days to decide on a course to take, after which time he or she could be starved into submission. However, there were some 20 places in England where the king's law had no power and the refugee could stay for life. Kings Henry VIII and James I limited sanctuary; it finally disappeared in the 18c. [< Lat. sanctus = holy] -
Dictionary of Medieval Terms and Phrases. Christopher Coredon with Ann Williams.