To preserve silence in the cloister monks communicated using signs, which were
made with the hands and fingers. The codification of signs began at the reformed
Benedictine house of Cluny in the tenth century, and was soon taken on by other
orders. A surviving Clairvaux manuscript contains a list of 227 signs which
were made using the fingers and hands. Signing was intended to convey essential
information; it was not meant for conversation or as an excuse for frivolity.
At Lent the Cistercians did not simply follow an abstemious diet but were also
urged to minimise speech and signing, thus fasting with the tongue and hands
as much as the stomach.