Perpetual Calendar Medal Using the Julian Calendar, Easter 1716


This is one of two English perpetual calendar medals in the collections using the Julian (rather than the present-day Gregorian) calendar. The Gregorian calendar would not be adopted in England until 1752. The small metal disc contains a wealth of calendrical information.

One side of the object has six concentric scales. The outermost scale give, for successive leap years, the day of the week of March 1 (the first day of the new year in the Julian calendar), as well as the date of Easter in successive years (with 1 indicating the month of March and 2 indicating April). Text next to this scale reads: EASTER (/) 1716.

The next innermost scale relates to times of the moon’s southing (e.g. the time the moon crosses the local meridian). It is labeled: SOUTH. The next innermost scale indicates the age of the moon on March 22 of successive years. This, the epact, increases by 11 days each year. The scale is labeled: EPACT. The three central scales on this side of the medal allow one to estimate the time of sunset for various days of the year. There is a central image of a setting sun.

The reverse side of the medal has a 7 x 7 calendrical table. The first two rows serve as heads of columns, indicating months which begin on the same day of the Julian calendar. These are 9 and 1 (November and March), 6 (August), 11 and 3 (January and May), 8 (October), 5 and 2 (July and April), 10 and 7 (December and September), and 12 and 2 (February and June). Note that in later calendrical styles, January and February would be in the next year.

The day of the week represented by the numbers in a column depended on the year. For example, in the Julian calendar for 1716, the columns indicate dates of Tuesdays. November and March had Tuesdays with dates 1, 8, 15, 22, and 29; August had Tuesdays with dates 2, 9, 16, 23, and 30; and so forth. Below the rows relating to months are five rows with squares numbered from 1 to 31. A mark in the last row reads: ABUCKLEY.

Compare MA.316919.2.

The object came to the Smithsonian from the collection of Henry Russell Wray.

Ackermann describes a single year calendar medal made by the English maker Andrew Buckley and refers to other calendar medals of his make.


Silke Ackermann, “Maths and Memory: Calendar Medals in the British Museum Part I,” The Medal, Autumn, 2004, vol. 45, esp. pp. 18-20. Another example, unsigned, which has been attributed to Buckley and is a perpetual calendar, has British Museum catalog number 1906,1103.4743. A single year calendar medal signed by him has number 1901,1115.4. Both are described at the website of the British Museum.

Date Made: ca1715Date Made: delete

Maker: Buckley, Andrew

Location: Currently not on view

Place Made: United Kingdom: Grand Bretagne

Subject: MathematicsCalendar


See more items in: Medicine and Science: Mathematics


Exhibition Location:

Data Source: National Museum of American History

Id Number: MA.316919.1Catalog Number: 316919.1Accession Number: 228694

Object Name: calendar medal

Physical Description: brass (overall material)Measurements: overall: .1 cm x 4 cm x 4 cm; 1/32 in x 1 9/16 in x 1 9/16 in


Record Id: nmah_1213998

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