Ancient History & Civilisation

APPENDIX K Calendars and Dating Systems in Thucydides

©1. The Modern, Western, Christian system of indicating years by assigning them numbers from a single point in time and then designating them consecutively as B.C. or A.D. obviously did not exist in the classical Greek world. Ancient Greek city-states used a completely different system based on local arrangements: each city-state identified a particular year by the name of the person who held a specified religious or political office in that particular city-state during that year. Therefore, the same year was known by a different designation in every city-state.

©2. Thucydides illustrates the complexity of Greek dating systems with his famous attempt in Book 2.2.1 to specify the date at which hostilities first broke out in the Peloponnesian War. The war began, he reports, when at Argos the priestess Chrysis was serving in her forty-eighth year, when at Sparta the political office of ephor (see Glossary) was held by Aenesias, and when at Athens the office of archon (see Glossary) was held by Pythodorus (see ©5 below for Thucydides’ reference to months at this point).

©3. Thucydides gave three different references to make the date of the first year of the war understandable by as many people as possible; that is, he hoped that any particular reader would be able to make sense of at least one of these three systems. To do so, of course, a reader would have needed a list that recorded in chronological order the names of the holders of the office being used as a standard of reference. By the fifth century B.C. city-states officially compiled lists of this sort, but ordinary people were unlikely to have had personal copies because they had no need of them for everyday purposes. Making correspondences between different local systems for indicating years, as Thucydides did, required research. He expected his readers to use the chronological fixed point of the first year of the war to calculate the date of other important events in his history, most notably the Thirty Years’ Peace between Athens and Sparta that he says (1.87.6; 2.2.1) had been negotiated fourteen years earlier.

©4. The only non-local Greek system for indicating the dates of years was based on the celebration of the Olympic Games, which took place every four years. Each period of four years (called an “Olympiad”) was numbered consecutively, starting with Olympiad I, which was agreed to have begun in the year that we designate as 776 B.C. An individual year could then be specified as year one, two, three, or four of a certain Olympiad. As Thucydides’ failure to give an Olympiad date for the opening of the Peloponnesian War implies, this system of reference seems not yet to have been in use at the time when he wrote. All he could probably do to derive chronological information from the Olympic record was to consult a list of victors in the games for a rough approximation of the time when someone like Cylon, whose victory he mentions at 1.126.3 as evidence of the man’s eminence, had lived. As his imprecise dating of Cylon to “former generations” reveals, he could not hope for much precision from this source.

©5. In Book 2.2.1 Thucydides also mentions that Pythodorus’s annual term as archon still had two months to run. Since Greeks divided the calendar of the year into twelve months, a reader who knew that the Athenians reckoned the year to begin around midsummer could deduce that the war had begun about two months before that season. To make matters more complicated, different city-states had different dates for New Year’s and different names for the months. Thus, when in 423 B.C. the Athenians and the Spartans agreed on the date upon which an armistice was to begin, the same day had to be specified according to the differing calendars of the two city-states: the fourteenth day of the month Elaphebolion according to the Athenian calendar and the twelfth day of the month Cerastius according to the Spartan calendar.

©6. Greeks reckoned months according to observation of the changing phases of the moon, which meant their months were generally twenty-nine or thirty days long. Since twelve lunar months amounted to a smaller number of days than the slightly more than 365 days in a solar year, Greeks had to add extra days to the annual count to try to keep their cycle of months synchronized with the year and its seasons. Such days are said to be “intercalated,” that is, inserted between other days.

©7. Since no uniform method existed for inserting extra days, sometimes officials would insert days into the calendar for religious or political reasons rather than merely to fill out the solar year. Thucydides reports (5.54.3), for example, that the Argives began a military expedition to invade their neighbor Epidaurus on the third day before the end of the month that preceded the month called Carneia by Dorian-speaking Greeks. Carneia was a month that Greeks of Dorian origin regarded as sacred and therefore off-limits for waging war. The Argives, who observed this custom, manipulated the calendar by repeatedly inserting another “third day before the end of the month” every day that they were in the field. That is, they kept designating each day of their expedition as the same day in the calendar. Since in this way they postponed the start of the month Carneia, they could continue to fight without committing any religious impropriety. When they returned home, they could then resume the regular progress of their calendar.

©8. Thucydides explains (5.20.2) that he devised his own system of time reckoning to use in his history because he wanted a greater precision than reference to the names of officeholders allowed. His system divided time into summers and winters. “Winter” referred to the period of several months each year when Greek armies and navies generally refrained from conducting military operations for fear of inclement weather. “Summer” referred to a longer period that more or less encompassed what we mean by the seasons of spring, summer, and fall, when war could for the most part be conducted at will. Thucydides’ idiosyncratic system made sense for a narrative like his that was organized around the rhythm of the military campaigns of a protracted war.

Thomas R. Martin
Classics Department
College of the Holy Cross
Worcester, Massachusetts

Athens selected nine archons every year. The one whose name was used to designate the year is known as eponymous, meaning “giving his name to.”

The sophist Hippias, who lived from approximately 485 to 415 B.C., had compiled a list of Olympic victors, but numbering Olympiads to yield dates did not take place until the fourth century B.C.

Thucydides, 4.118.12, 4.119.1.

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