Abstract
From the very beginning, silence was one of the most important rules governing monastic life. However, in order to be able to communicate even where the commandment of silence demanded absolute silence, a sign language was developed that was used in many communities from the 10th century.
The monks and nuns were always admonished to only exchange messages that were indispensable for the practical and spiritual processes in the monastery. The sign language is recorded in so-called signa-lists, a kind of simple dictionary with mostly brief descriptions of how to represent an object, a person or another word to be signified by means of signs.
At the centre of this book is the sign language of the Cistercians. The surviving Cistercian sign-lists reveal information about daily life in the medieval monasteries and at the same time reflect the reform endeavours of their time.