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Olympic Dates

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These pages give access to conversion tables in Excel format, with copies in HTML format and in CSV format, useful for determining the Julian equivalent of years dated according to Olympiads during the Ptolemaic era. This system was used by Greek historians to provide a common frame of reference to reconcile historical dates given in many different local calendars. It is particularly important for interpreting the regnal years attributed to the Ptolemies by Porphyry, as transmitted through the works of Eusebius.

This page provides analyses of three topics related to the Olympiad system:

The most detailed Ptolemaic chronology transmitted to us in the classical literary tradition is that of Porphyry of Tyre. Porphyry was a pagan philosopher and historian writing in the third century AD (see his entry in the Suda). His historical works only survive to the extent that they were quoted by his Christian adversaries. His summary of Ptolemaic chronology was incorporated in book 1 of Eusebius' Chronicon, which was transmitted via the Armenian translation of that work and by incorporation of extracts into the works of the eighth century Byzantine chronographer George Syncellus, whence it was recovered by Scaliger. An English translation of Petermann's Latin translation of the Armenian translation of the original Greek (now represented only in Syncellus' version), taken from Schoene's edition of Eusebius, may be found here.

Only the Canon of Kings was more important in establishing the correct dates of Ptolemaic events before the discoveries of modern papyrology and epigraphy. Porphyry gives us much precise chronological information that allows us to explain features of the papyrological and epigraphic record which might otherwise be rather puzzling, including:

Nevertheless, his absolute chronology has been faulted for confusion and inaccuracy. In my view the charge is unfounded. His chronology is not quite as complete as one would like -- in particular, he does not date the death of Cleopatra III, and he does not align the years of Berenice IV with the rest of the Ptolemaic kings. However, the chronology he gives is almost entirely correct, and he remains extremely valuable. The problem lies in a misunderstanding of his system, which is much more straightforward than it is generally held to be.

The perceived problem with Porphyry's chronology is best seen by explaining its analysis by F. Jacoby, Die Fragmente der grieschischen Historiker IIB (Komm.) 854ff. Jacoby argued that Porphyry's regnal years are postdated, i.e. that Porphyry dates a reign as starting in the first full year after accession and finishing in the year in which the king died, which year was counted as a complete final year.

This is unquestionably the system used in his account of the Macedonian kings (FGrH 260 F 3(4)) following the death of Alexander III:

King

First Year

Last Year

 Length

Other data

Philip III

Ol. 114.2=323/2

Ol. 115.4=317/6

7 yr

6 years 4 months (Diodorus 19.11.5)

Cassander

Ol. 116.1=316/5

Ol. 120.3=298/7

19 yr

† Artemisios embolimos (Mac.)

Sons of Cassander

Ol. 120.4=297/6

Ol. 121.3=294/3

3 yr 6 m.

Thess: Philip IV 4 m, Antipater+Alex V 2 yr 6 m

Demetrius I

Ol. 121.4=293/2

Ol. 123.1=288/7

6 yr

Thessaly: 6 yr 6 m

Pyrrhus

-

Ol. 123.2=287/6

7 m.

Thessaly: 4 yr 4 m (or 3 yr 6 m)

Lysimachus

Ol. 123.2=287/6

Ol. 124.3=282/1

5 yr 6 m.

Thessaly: 6 yr

Seleucus

-

-

[7 m.]

† Ululu SEB 31 (Bab.) = 26 Aug./24 Sep. 281

Ptolemy Ceraunus

Ol. 124.4=281/0

Ol. 125.1=280/79

1 yr 5 m.

Meleager

-

-

2 m.

Antipater Etesias

-

-

45 d

Sositheus

-

-

2 yr

Thessaly: 1 yr

[Anarchy]

Ol. 124.4=281/0

Ol. 126.1=276/5

-

Thessaly: 2 yr 2 m

Antigonus II

Ol. 126.1=276/5

Ol. 135.1=240/9

44 yr

proc. Ol. 123.2=287/6; Thess: 34(33) yr 2 m

Demetrius II

-

Ol. 130.2=260/59?

10 yr

confused with Demetrius the Fair

Antigonus III

-

Ol. 139.4=221/0

12 yr

Philip V

Ol. 140.1=220/19

Ol. 150.2=179/8

42 yr

Thess: 42 yr 9 m over Macedon

Perseus

-

Ol. 152.4=169/8

10 yr 8 m.

Pydna: pr. Non. Sept. AUC 586 = 22 June 168

There are clearly problems with the accuracy and internal consistency of this account, notably with the reigns of the Antigonid kings. The Macedonian data also does not entirely match the data that Eusebius presents for Thessaly, also attributed to Porphyry (FGrH 260 F 31(5)); discrepancies are noted in the above table. However, it is clear that the list uses a convention that annexes partial years, and that the partial year annexed is normally the remainder of the year in which the king died, even though it was often recorded that the reign ended part way through the year -- i.e. that the reigns are postdated.

There is one apparent exception in this part of the list: year 1 of Lysimachus annexes the 7 months attributed to Pyrrhus. This possibly reflects the fact that Pyrrhus did not complete a full year, or, if the Thessalian numbers are correct, it may reflect a divided rule (cf. K. J. Beloch, Griechische Geschichte IV.2 107, 119). On the other hand, if the Thessalian list correctly reflects the breakdown of the reigns of the sons of Cassander, then the 4 months of Philip IV must have been accounted as a full year following the death of Cassander, and the reigns of Antipater and Alexander V were accounted as the following three years. However, these problems are chronological, and do not diminish the list as evidence of a chronographic convention of Porphyry's regnal dating.

The same convention is apparent in Porphyry's treatment of the Seleucids (FGrH 206 F 32(6)), which runs as follows, down to the death of Antiochus IX, at which point Porpyhry largely stops giving Olympic dates. Porphyry's data can be compared against BM 35603, a Babylonian kinglist, and information gleaned from other Babylonian sources, e.g. BM 32171:

King

First Year

Last Year

Length

Babylonian Sources
[year 1 (accession date), length, † (death) date]

Seleucus I

Ol. 117.1=312/1

Ol. 124.4=281/0

32 yr

SE 7, 25 yr, †Ululu 31=26 Aug./24 Sep. 281

Antiochus I

Ol. 125.1=280/79

Ol. 129.3=262/1

19 yr

SE 32, 20 yr, †16 Aiaru 51=2 June 261

Antiochus II

Ol. 129.4=261/0

Ol. 133.3=246/5

19 yr [?]

SE 52, 15 yr, †rpt 20 Abu 66=19 August 246

Seleucus II

Ol. 133.3=246/5

Ol. 138.2=227/6

21 yr

SE 67 (SE 66 Abu/Ululu), [20 yr]

Seleucus III

-

Ol. 139.1=224/3

3 yr

SE 87 (SE 86 Tebetu), [4? yr]

Antiochus III

Ol. 139.2=223/2

Ol. 148.2=187/6

36 yr

(SE 90), 35 yr, †25 Simanu 125=4 July 187

Seleucus IV

Ol. 148.3=186/5

Ol. 151.1=176/5

12 yr

(SE 125), 12 yr, †10 Ululu 137=3 Sept. 175

Antiochus IV

Ol. 151.3=174/3

Ol. 154.1=164/3

11 yr

(SE 137), 11 yr, †rpt Kislimu 148=20 Nov./18 Dec 164

Antiochus V

-

-

-

SE Arahsamnu 137-Abu 142=Oct/Nov 174-Aug. 170

Demetrius I

Ol. 154.4=161/0

Ol. 157.4=149/8

12 yr

-

Alexander I

Ol. 157.3=150/49

Ol. 158.4=145/4

5 yr

-

Antiochus VI

-

-

-

-

Demetrius II

Ol. 160.1=140/39

Ol. 160.3=138/7

3 yr

-

Antiochus VII

Ol. 160.4=137/6

Ol. 162.4=129/8

-

-

Demetrius II

Ol. 163.2=127/6 [?]

Ol. 164.1=124/3

4 yr

-

Seleucus V

-

-

[1 yr]

-

Antiochus VIII

Ol. 164.2=123/2

Ol. 166.4=113/2

11 yr

-

Antiochus IX

Ol. 167.1=112/1

Ol. 171.1=96/5

18 yr [?]

-

Antiochus VIII

Ol. 167.2=111/0

Ol. 170.4=97/6

15 yr

-

As with the Macedonian list, there are some problems with this list, and with synchronising it to the Babylonian data, particularly if one assumes (as seems natural) that the ultimate source of Porphyry's data was a list dated using the Seleucid Macedonian calendar. However, it is also clear that the list generally follows the chronographic conventions of the Macedonian list: a king's first year is the year following the death of his predecessor, and the full year in which he died is accounted as his last.

With this background we may now examine Porphyry's Egyptian chronology (FGrH 260 F 2), comparing it to that of the Ptolemaic Canon:

King

Reign-length
(Ptolemy)

Reign-length
(Porphyry)

Porphyry's Notes

Philip III

7

1

Out of 7 (starts in Ol. 114.2 in Armenian text)

Alexander IV

12

-

(Not in Porphyry)

Ptolemy I

20

17+23=40-2=38

17 (Satrap) + 23 (king) - 2 (coregent)

Ptolemy II

38

38

Including 2 years of coregency

Ptolemy III

25

25

-

Ptolemy IV

17

17

-

Ptolemy V

24

24

(23 in Armenian text)

Ptolemy VI+Ptolemy VIII

35+29=64

64=11+6+18+29

1 Ptolemy VIII = 12 Ptolemy VI

Ptolemy IX+X+Berenice III

36

36=10+18+7.5+0.5

1 Ptolemy X = 4 Ptolemy IX

Ptolemy XII

29

29

Inc. 3 of Berenice IV

Cleopatra VII

22

22=4+4+7+7

Ptolemy XIII+XIV+sole reign+double dates

TOTAL

294

294

Duration: Ol. 111.1 to Ol. 184.2 = 293 years

As noted above, the text is known in Greek and Armenian versions; the latter is generally available translated into Latin (Petermann apud Schoene) and German (Jacoby, as FGrH 260 F 2). The two versions are slightly different. In general the Greek appears to be more accurate.

By contrast with his Macedonian and Seleucid lists, Porphyry dispenses with Olympic dates entirely in this list. While it is apparently bracketed by two Olympic dates, both are problematical.

The commentators I have seen have assumed that the postdating seen in Porphyry's Macedonian and Seleucid lists must also apply to the Egyptian list. This results in the following absolute chronology, which we may compare with the actual dates determined from other data:

King

Reign-length
(Porphyry)

Dates
(Postdated)

Dates
(Actual)

Philip III

1

323/2

-

Ptolemy I

38

322/1-285/4

June 323 - [Feb.] 284

Ptolemy II

38

284/3-247/6

[Feb.] 284 - Jan. 246

Ptolemy III

25

246/5-222/1

Jan. 246 - Dec. 222

Ptolemy IV

17

221/0-205/4

Dec. 222 - c. Aug. 204

Ptolemy V

24

204/3-181/0

c. Aug. 204 - Sep. 180

Ptolemy VI+Ptolemy VIII

64

180/79-117/6

Sep. 180 - June 116

Ptolemy IX+X+Berenice III

36

116/5-81/0

June 116 - March 80

Ptolemy XII

29

80/79-52/1

March 80 - Feb 51

Cleopatra VII

22

51/0-30/29

Feb 51 - Aug. 30

TOTAL

294

323/2-30/29

293 years 2-3 months

There are two evident problems with this. The first is that Porphyry's years total 294 years, not his stated 293; moreover, the actual elapsed time is 293 years and a couple of months. The range of dates Ol. 114.1 = 324/3 to Ol. 187.2 = 31/0 also covers 294 years if counted inclusively. The second problem is that Cleopatra VII's last year, in which she died, is calculated to be 30/29, not 31/30 as Porphyry appears to have believed. (That Philip III's first year is given as 323/2 is not necessarily a problem, since in a postdated system this would be counted as his first year if he acceded in Ol. 114.1 = 324/3.)

Jacoby suggested that Porphyry's source might have been based on the Attic calendar, in which case Cleopatra VII's death would indeed have fallen in 30/29. A. E. Samuel, Ptolemaic Chronology 14, noted that this proposal would also explain why Ptolemy I's year 1 was accounted as 322/1, since he could only have taken up his office as satrap in the Athenian year 323/2, and that this receives support from pOxy 1.12 = FGrH 255.9. Samuel himself, however, argues that the resolution to the problem lies in the year attributed to Philip III, which he proposes to remove. He does not notice that the effect of this is to cause the rest of the chronology to be antedated rather than postdated.

Additional problems arise when we compare Porphyry's account of the reigns of Ptolemy VI and Ptolemy VIII against the contemporary sources. Egyptian regnal years are antedated. We would therefore expect that the Egyptian year for a given date would normally either be the same as or one higher than Porphyry's regnal year for the same date. Porphyry says that Ptolemy VI ruled alone for 11 years and then with Ptolemy VIII, that the first year of the coregency was called the 12th of Ptolemy VI and the 1st of Ptolemy VIII, and that the two brothers ruled together up to the 17th year and that from the 18th Ptolemy VI again ruled alone. These numbers match perfectly what we see in the Egyptian papyri, and the earliest document from the joint rule is dated in Thoth. Assuming that Porphyry was postdating, A. E. Samuel Ptolemaic Chronology 141, concludes that the only way to reconcile the two systems is to suppose that the coregency actually started on 1 Thoth, so that the postdated year number also equals the antedated year number (and, incidentally, implying that Porphyry's Olympic years are aligned to the Egytian year at this time).

Possibly. However, Samuel ignores Porphyry's second statement: that after Ptolemy VI's death Ptolemy VIII numbered his years from the coregency, so that "the 36th year of Philometor should have been called the first year of his reign, but instead he ordered it to be written as the 25th year of his reign". If Porphyry was postdating, the last year of Ptolemy VI's reign, in which Ptolemy VIII succeeded him, should have been his 35th. The statement only makes sense if Porphyry was antedating at this point, so that his regnal years at this time were either identical to or closely aligned to Egyptian regnal years. In fact Samuel himself (A. E. Samuel, CdE 40 (1965) 376) later concluded that Porphyry's account of the reigns of Ptolemy IX and Ptolemy X must have been based on the Egyptian calendar, without taking into account the implications of this result for the remainder of Porphyry's Egyptian chronology.

In fact almost everything falls into place immediately if one simply assumes that Porphyry's data is ultimately taken from an Alexandrian source and reflects Alexandrian dating conventions. If so, his regnal years would not be postdated but antedated. In this case, the chronology is aligned as follows (with the accession year estimated according to the Macedonian calendar reconstruction developed here):

King

Length
(Porphyry)

Dates
(Antedated)

Accession Year
(Regnal)

Dates
(Actual)

Philip III

1

324/3

c. 21 Sep. 324 - c. 9 Oct. 323

-

Ptolemy I

38

323/2-286/5

11 June 323 - c. 30 June 322

June 323 - [Feb.] 284

Ptolemy II

38

285/4-248/7

c. 11. July 286 - c. 29 June 284

[Feb.] 284 - Jan. 246

Ptolemy III

25

247/6-223/2

c. 8 June 247 - c. 28 May 246

Jan. 246 - Dec. 222

Ptolemy IV

17

222/1-206/5

c 28 Aug. 222 - c. 22 Aug. 221

Dec. 222 - c. Aug. 204

Ptolemy V

24

205/4-182/1

c. 24 Sep. 205 - c. 12 Oct 204

c. Aug. 204 - Sep. 180

Ptolemy VI+VIII

64

181/0-118/7

c. 29 Sep. 181 - c. 18 Sep. 180

Sep. 180 - June 116

Ptolemy IX+X+Ber. III

36

117/6-82/1

21 Sep. 117 - 20 Sep. 116

June 116 - March 80

Ptolemy XII

29

81/0-53/2

12 Sep. 81 - 11 Sep. 80

March 80 - Feb 51

Cleopatra VII

22

52/1-31/0

5 Sep. 52 - 4 Sep. 51

Feb 51 - Aug. 30

TOTAL

294

324/3-31/0

 

293 years 2-3 months

On this basis, Porphyry's regnal years align well with Egyptian regnal years after Ptolemy I because they are one and the same. The interval covered by the Egyptian list becomes exactly aligned with Porphyry's statement of the first and last Olympic years of the dynasty (as emended by Jacoby). The year of Philip III covers the period between Alexander's death and Ptolemy I's arrival in Egypt. The 294th year is the last year of Cleopatra VII, which would normally be the first year of Augustus, just as Porphyry assumed -- but in fact was not, because Augustus attempted, unsuccessfully, to introduce an anniversary-based regnal year into Egypt.

I see only two problems with the accuracy of the resultant chronology:

25 Nov. 2006: Add dates of regnal year 1

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