Egyptian Dates

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Civil dates: (Excel) (HTML) (CSV)                                                   Lunar cycle: (Excel) (HTML) (CSV)

This page gives access to a set of conversion tables for determining the Julian equivalent of Egyptian civil and lunar dates in the Ptolemaic era. Two tables are provided: a table converting civil dates to Julian dates, and a table notionally converting lunar dates to civil dates according to the lunar cycle of pCarlsberg 9.

How to Read the Lunar Cycle Table                                         How to Read the Civil Conversion Table

The table gives the Egyptian civil date, according to the wandering year, of first day of each notional lunar month of the 25-year cycle of pCarlsberg 9, as reconstructed by Depuydt in W. Clarysse et al. (eds), In Mem. Quaegebeur II 1277.

The start date of blue months or epagomenal months, which Depuydt regarded as uncertain, are italicised; the alternate start date is one day later.

While the Depuydt reconstruction is used here, the most widely used reconstruction is the older one of R. A. Parker, The Calendars of Egypt 24ff. Months in which the Depuydt and Parker interpretations differ are highlighted in blue; in each case, Depuydt's reconstruction is one day earlier than Parker's.

How to Use the Lunar Cycle Table

Depuydt regarded the Carlsberg calendar as an arithmetical exercise in distributing 29-day months according to the simplest possible algorithm, not as a real calendar. The available lunar dates support this view, at least for dates before AD. 44. Nevertheless, the pdem Carlsberg 9 reconstructions may still be useful for estimating conversions between lunar and civil dates that are accurate to within a day or two.

In order to convert a civil date into a (nominal) lunar date, one proceeds as follows:

In order to convert a lunar date into a (nominal) Julian date, one proceeds as follows:

In practice, the most significant chronological use of lunar dates has been to resolve ambiguities in civil dates (typically, formulae of the form Year <N> <civil date> = <lunar day>, where the ruler is not given). In this case one proceeds as follows:

Since the cycle is notional, and not necessarily historically or astronomically correct in any given instance, any given conversion is subject to a margin of error of one or two days. Therefore, in addition to direct matches, it is sometimes wise to determine the year number for matches that differ by one day.

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