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perpetual calendar medal

  • Object type

  • Museum number


  • Description

    Silver perpetual calendar medal. Perpetual calendar table and surrounding inscription. Two concentric circles of inscriptions, with key to perpetual calendar on obverse and Epact table, surrounding 'horoscopic' square with central dot, each space between the square and the surrounding circle containing a half-floret and three concentric lines; with starting date of calendar.


  • Date

    • 1684
  • Production place

  • Materials

  • Technique

  • Dimensions

    • Diameter: 31 millimetres
    • Weight: 5.34 grammes
    • Die-axis: 90 o'clock
  • Inscriptions

      • Inscription Type

      • Inscription Position

      • Inscription Language

      • Inscription Content

        .A . PERPETVAL . . ALMANACK . . OF EXCELLENT . . & . READY . VSE . .
      • Inscription Comment

        clockwise around the edge
      • Inscription Type

      • Inscription Position

      • Inscription Content

        2 7 4 12 6 3 11
        5 10 0 1.9 0 0 8
        1 2 3 4 5 6 7
        8 9 10 11 12 13 14
        15 16 17 18 19 20 21
        22 23 24 25 26 27 28
        29 30 31 0 0 0 0
      • Inscription Type

      • Inscription Position

      • Inscription Content

        (floret) 1684 MT W T F SS M T W TF S S M TW T F S SM T W T FS S M T WT F S S
      • Inscription Comment

        outer concentric circle divided into 29 fields; '(floret) 1684' in one large field at top; each single-letter field also containing a half-floret
      • Inscription Type

      • Inscription Position

      • Inscription Language

      • Inscription Content

        Epact 23 4 15 26 7 18 29 11 22 3 14 25 6 17 28 9 20 1 12
      • Inscription Comment

        inner concentric circle divided into 20 fields; surrounding central 'horoscopic' square
  • Curator's comments

    This is one of the earliest known examples of English calendar medals. The medal can be used to calculate the week day of any date and the date of Easter. The obverse of the disc is marked with a scale for the 28 year solar cycle, starting with the year 1684 and March as the first month of the year; the centre bears a table of epacts. The reverse displays a table of months and days. Marked.
    [S. Ackermann 1999]

    The figures in the two top rows of the calendrical table on the obverse indicate the months according to the Julian calendar, with March as the first month of the year (so 1 = March, 2 = April, and so on). 1684 was a leap year, but the table is given according to the layout for an ordinary year with the Dominical Letter G.
    The outer circle on the reverse starting with 1684 determines the reading of the table on the obverse: as MT is given for 1684, the table becomes a table of Mondays before the insertion of the leap day and a table of Tuesdays for the period after the leap day. A sequence for 28 years, that is 1684 to 1711, is given. Thus in 1685 the table becomes a table of Wednesdays, for 1686 a table of Thursdays, and so on. For 1684 this means that 1, 8, 15, 22 and 29 (in the first column on the left) of April and July are Tuesdays, and so are 2, 9, 16, 23 and 30 of September and December in the second column. It should be noted that January (11) and February (12) are given as if they were the first two months of the year (as though the year started in January), when strictly speaking they should be given as the last two months of the year, thus coinciding with January and February of 1685. Cf. [Ackermann 2004] cat. nos. 5-11 and [Ackermann 2005] cat. no. 113 [reg. nos. OA 2428; 1908,9-14.144; 1901,10-18.7; 1901,10-18.8; 1888,12-1.333; OA 2429; J.3200; and 2004,0923.1].
    The Epact table in the inner ring gives the Julian Epacts for 19 years starting with 1684 (for the use and function of Epacts, see [Ackermann 2004] p. 8).
    The medal enables the user to determine the week-day of any given year between 1684 and 1711 and, as the solar cycle repeats itself every twenty-eight years (for the solar cycle see [Ackermann 2004] p. 8) multiples of twenty-eight years before and after these dates. The Epact table helps with the date of Easter Sunday for any given year between 1684 and 1702 and, as the lunar cycle repeats itself every nineteen years (for the lunar cycle see [Ackermann 2004] p. 8) multiples of nineteen years before and after these dates. However, an additional set of tables is necessary to perform this calculation.
    [Ackermann 2004, p. 16f., with additions]


  • Bibliography

    • Ackermann 2004 4 bibliographic details
  • Conservation

    See treatments 

    Treatment date

    2 April 2004

    Treatment proposal

    Light clean and remove heavier surface deposits.


    Surfaces dirty with a waxy grime, dust and spots of thick white waxy deposits which obscures detail.. No active corrosion

    Treatment details

    Cleaned using Industrial methylated spirits (ethanol, methanol) applied on cotton wool swabs.Brush with dry natural bristle brush.

    About these records 

  • Acquisition name

  • Acquisition date


  • Department

    Britain, Europe and Prehistory

  • Registration number



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Object reference number: MCC6902

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