Canonical sundial

A canonical sundial indicates the canonical hours of formal ritualistic acts. Such sundials were used from the 7th to the 14th centuries by members of religious communities.

A canonical sundial is a fairly small carving on the south wall of a medieval religious building. The canonical sundial's purpose is to indicate the canonical hours when members of the community must perform certain religious acts, not to give the time of day.

The dial is usually a semi-circle, divided into 4, 6, 8, or 12 equal sectors. At the center of the circle, a horizontal stylus, perpendicular to the wall, casts its shadow on the sectors, giving the 'canonical hour'. The original wooden styli have long since disappeared, leaving a circular hole.

The dials are called 'canonical' because they mark the canonical hours. By convention, when the shadow of the stylus falls on one of the dividing lines of a sector, the corresponding prayers must be said. There were no numerical indications on the dial.

The dials were usually placed near the priests' door on the south side of the church at eye level. In an abbey or large monastery the dials were usually carefully carved in the stone walls. In rural churches they were very often just scratched on the wall, and it is sometimes difficult to distinguish them from graffiti.

During the 6th and 7th centuries each congregation had its own specific rites, and the number of graduations on the early canonical sundials varies. From the 8th century onwards the Rule of Saint Benedict, used by Benedictine and Cistercian communities was generally adopted.

The eight celebrations are: Matins/Vigils, Lauds, Prime, Terce, Sext, None, Vespers and Compline. Matins, Lauds and Compline usually occur during the night hours.

St. Michael's church
Coningsby, Lincolnshire UK

St. Martin Fresney-le-Puceaux, Calvados France

St. Pierre-du-Palais
Charente-Maritime France

St Peter's church
Marsh Baldon, Oxfordshire UK

The Bewcastle Cross (7th century), Nendrum Monastery (9th century) and Kirkdale (11th century) dials are well-known examples of the canonical sundial. The Bewcastle Cross is the oldest known canonical sundial in England, carved on a Celtic cross in the church graveyard, and the Nendrum Monastery sundial gives the name of the sculptor and the priest.

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Wikipedia