CURFEW, or Curfew-sen, a signal, as by tolling a bell, to warn the inhabitants of a town to extinguish their fires and lights and retire to rest. This was a common practice during the middle ages, especially in cities taken in war. In the law Latin of those times it was termed ignitegium, or pyritegium.

The curfew is commonly said to have been introduced into England by William the Conqueror, who ordained, under severe penalties, that at the ringing of the curfew-bell at eight o'clock in the evening all lights and fires should be extinguished. It seems probable, however, that he merely enforced an existing and very common police regulation to that effect. The curfew-bell was abolished by Henry I. in 1100. The practice of tolling a bell at a fixed hour in the evening, still extant in many places, is a remnant of the ancient curfew.

As a precaution against conflagrations, the curfew was a most useful regulation, at a period when it was the custom to place the fire in a hole in the middle of the floor, under an opening in the roof to allow the escape of the smoke. When a family retired to rest for the night, the fire was extinguished by covering it up; and hence the term curfew-sen, or curfew. But this salutary regulation served another important end, since by obliging people to keep within doors, nocturnal brawls in the streets were in a great measure prevented. The severity exhibited by William the Conqueror in enforcing obedience to the curfew, appears to have been more particularly designed to prevent the English from assembling in secret to plan schemes of rebellion against himself.

The ringing of the prayer-bell, as it is called, which is still practised in some Protestant countries, originated in that of the curfew-bell. Pope John XXXIII., dreading that misfortunes were about to befall him, ordered every person on hearing the ignitegium to repeat the Ave Maria three times, with a view to avert them. When the appearance of a comet, and a dread of the Turks, alarmed all Christendom, Pope Calixtus VIII. increased these periodical times of prayer, by ordering the prayer-bell to be also rung at the hour of noon.