St. Gallen, Stiftsbibliothek, Cod. Sang. 533 : Directorium perpetuum of the Monastery of St. Gall, Serie prima, Regulae 1-2

The Directorium perpetuum of the monastery of St. Gall, commissioned by Abbot Franz von Gaisberg (1504–1529), consists of seven volumes (Cod. Sang. 533–539). A total of 36 regulae contain the liturgical rules for the Liturgy of the Hours for all possible annual calendars, due to the variable date of Easter. Each rule begins with Epiphany; the rules for the holidays of the Christmas season until th…