This manuscript deals with the calculation of Easter Sunday according to the Coptic calendar. Fixing this date each year governs much of the liturgical and devotional life of the Coptic Orthodox Church. The Coptic calendar begins in 284 AD, which is called Anno Martyrum (AM), or Year of the Martyrs. The first folio contains a table of the four seasons with their corresponding Coptic months and zodiacal signs. The following pages, some of which are torn or badly stained, provide instructions for calculating the movement of the moon and reconciling the Coptic and Arabic (Islamic) calendars. There are also instructions for fixing the date of saints’ days and other feasts and fasts, such as the Fast of the Apostles, which are set in relationship to Easter. Numerous tables calculate the dates of the Niruz or Nawruz (Egyptian New Year) from the creation of Adam. There are also forward projections, dating Easter from the Creation and the Incarnation until around the year 1900. At the end of the volume is a reflection by the monk who wrote this work, Butrus Girgis, on his spiritual renewal. The date of the work is uncertain, but a short autobiographical note suggests it was written in the 1860s. The volume is poorly bound. Its title page is missing, and some internal pages are torn or stained and illegible where ink has bled through the paper. The work is part of the Iryan Moftah Collection of Coptic Books and Manuscripts at the American University in Cairo.