The monasterial rule (which before the general introduction of clocks was commonly followed by the mediÃ¦val public in the computation of time) divided the twenty-four hours of the day and night into seven parts (six of three hours each and one of six), the inception of which was denoted by the sound of the bells that summoned the clergy to the performance of the seven canonical offices i.e.
at 3 AM, Prime
at 6 AM, Tierce
at 9 AM, Sexte
or Noonsong at Noon, None
at 3 PM, Vespers
or Evensong at 6 PM and Complines
or Nightsong at 9 PM, and at the same time served the laity as a clock.
The Decameron: The Classic Translation of John Payne, by Giovanni Boccaccio, John Payne (Translator)
||Sexte or Noonsong
||Vespers or Evensong
||Complines or Nightsong