SELEUCID ERA, the first system of continuous year numbering, introduced in the Middle East by the Seleucids, and the direct forerunner of the Christian, Islamic, and Jewish years. As the formal time reckoning system of the Seleucid empire, the era was adopted throughout the Middle East. Sometimes known as the Era of the Greeks (e.g., 1 Maccabees 1:10), its use became widespread and outlived the Seleucids by centuries, surviving in some parts of the Middle East until the twentieth century.

Year 1 of the Seleucid Era (SE) is 312/11 BCE, the first regnal year of Seleucus I Nicator (q.v.). Presumably, it was not Seleucus himself who initiated the era but his successor Antiochus I Soter (281-261 BCE); instead of counting the years from his own accession anew, Antiochus continued to count from 312/11. In fact, Seleucus Nicator had not really been king in 312/11, since at that time he still officially acknowledged Alexander the Great’s son Alexander IV as ruler of the Macedonian empire. Babylonian documents use the regnal years of Alexander IV posthumously as late as 306/5 BCE (Wacholder, 1984, concluding that Alexander IV did not die until 305). Although Seleucus may have assumed a royal title vis-à-vis his Babylonian subjects during the period of interregnum following the assassination of Alexander IV (the date of which is uncertain, perhaps 310/9), it was not until 305/4 that he adopted the more pretentious Greek title of basileus. After 304, however, Seleucus antedated his reign to Nisannu 1 (April 3) of the Babylonian year 312/11, the year in which he had returned from exile to wrest his satrapy of Babylonia from the hands of his foe, Antigonus Monophthalmus. His successor Antiochus I then continued this counting.

It is difficult to explain why Antiochus propounded this consequential innovation of the calendar. E. J. Bickerman (1943-44) believed that it was designed to solve some complications involved in the Seleucids’ efforts to harmonize Macedonian and Babylonian months (see below). W. V. Hallo (1984-85) suggested that it, rather, sprang from the fact that Antiochus had already been king together with his father for twelve years when Seleucus died in 281: rather than calling his first year as sole ruler either his 13th or 1st regnal year, Antiochus chose to call it the 31st of his dynasty, and his successors, who likewise appointed sons as co-rulers to secure a harmonious succession, continued the counting for the same reason. Continuous counting of years in itself was not new, as this had been done since the eighth century BCE by Babylonian astronomers in order to calculate long-term celestial phenomena, but this practice was not yet used as an universal dating system. It is disputed whether there existed in actuality a short-lived Nabonassar Era, initiated by the Babylonian king Nabu-nasir (r. 747-734), and mentioned in the writings of Berossus and Ptolemy (cf. Hallo, 1988, arguing in favor of its historicity). From an ideological viewpoint, the Seleucid Era may be connected with the fundamental notion in Hellenistic royal ideology of an everlasting Golden Age, a re-beginning of history, brought about by the benevolent and victorious king and his dynasty (Strootman, 2007, pp. 348-56; cf. Strootman, 2014).

Calculating years in SE is not without problems, because the Seleucids used both the Babylonian and Macedonian calendars (the latter perhaps only for the sake of Greek-speaking subjects; see Samuel 1972, p. 142). The Babylonian year began at the spring equinox with the month Nisannu (Old Persian Adukanaiša) in March-April, the Macedonian calendar at the autumn equinox in September-October (on this problem see Bickerman, 1943, pp. 73-76; cf. Cohen, 1993). To synchronize time reckoning, the early Seleucids reformed the Macedonian calendar, assimilating Macedonian months with Babylonian and Persian ones, so that the first Macedonian month Dios corresponded with Babylonian Tašrîtu and Persian Bâgayâdiš (Hannah, 2005, pp. 94-95). Still, the problem remains that for the modern historian it is sometimes unclear whether a date given in SE refers to the Macedonian or the Babylonian year. 

When the Seleucid empire declined, various successor dynasties proclaimed new imperial eras, claiming the status of Great King as heirs or conquerors of the Seleucids. Thus, a Parthian Era (see ARSACIDS v) based on the Seleucid calendar was institutionalized at an unknown date at the end of the second century BCE, antedating the foundation of the Parthian empire to 247/6. About the same time, Mithradates VI of Pontos likewise took the title of great king and introduced a short-lived Pontic Era (Reinach, 1902; McGing, 1986). To challenge Parthian claims to Asia, Marc Antony and Cleopatra VII initiated a new epoch and year reckoning for the Middle East in 37/6 BCE (Schrapel, 1996, pp. 209-23), but this Golden Age lasted less than a decade. Ultimately, the Seleucid Era continued to be the predominant system of year counting in the western parts of the Middle East centuries after the Seleucid kingdom had vanished from history. In Syria it was used on inscriptions as late as the sixth century CE, until it was finally replaced by the Islamic Year. Some Christians in the Near East, however, continued to use the era; in the liturgy of the Assyrian church it even remained in use until the twentieth century.

In Iran and further east, the Seleucid Era was superseded by new imperial eras from the first century BCE onwards. Coins dated to the Parthian Era turn up in the reign of Phraates IV (ca. 37-2 BCE) (Sellwood, 1980, p. 16); before that time, Parthian coins were either undated or dated to the Seleucid Era (Wroth, 1903, p.  lxiii). An epoch called Bactrian Era by modern scholars, dating its beginning to 155 BCE, was used on Indo-Greek coins. On Kushan inscriptions we find a so-called Saka Era, starting with year 1 of the emperor Kanishka, who probably reigned in the second century CE (Frye, 1996, p. 136).




E. J. Bickerman, “Notes on Seleucid and Parthian Chronology,” Berytus 8, 1943-44, pp. 73-83

M. E. Cohen, The Cultic Calendars of the Ancient Near East, Bethesda, 1993.

W. V. Hallo, “The Concept of Eras from Nabonassar to Seleucus,” Journal of the Ancient Near Eastern Society of Columbia University 16-17, 1984-85, pp. 143-51. Idem, “The Nabonassar Era and Other Epochs in Mesopotamian Chronology and Chronography,” in E. Leichty et al., eds., A Scientific Humanist. Studies in Memory of Abraham Sachs, Sheffield, 1988, pp. 175-90.

R. Hannah, Greek and Roman Calendars. Constructing Time in the Classical World, London, 2005.

R. N. Frye, The Heritage of Central Asia. From Antiquity to the Turkish Expansion Princeton, 1996.

B. C. McGing, “The Kings of Pontus. Some Problems of Identity and Date,” Rheinisches Museum für Philologie, N.S. 129, 1986, pp. 248-59.

Th. Reinach, “Some Pontic Eras,” Numismatic Chronicle 2, 1902, pp. 1-11.

A. E. Samuel, Greek and Roman Chronology, Munich, 1972.

D. G. Sellwood, An Introduction to the Coinage of Parthia, London, 1971; 2nd ed.,  1980.

R. Strootman, “The Hellenistic Royal Court. Court Culture, Ceremonial and Ideology in Greece, Egypt and the Near East, 336-30 BCE,” diss. Utrecht, 2007.

Idem, “The Dawning of a Golden Age: Images of Peace and Abundance in Alexandrian Court Poetry in the Context of Ptolemaic Imperial Ideology,” in M. A. Harder, R. F. Regtuit, and G. C. Wakker, eds., Hellenistic Poetry in Context, Hellenistica Groningana 20, Leuven, 2013, pp. 325-41.

B. Z. Wacholder, “The Beginning of the Seleucid Era and the Chronology of the Diadochoi,” in F. E. Greenspahn, E. Hilgert, B. L. Mack, eds., Nourished with Peace. Studies in Hellenistic Judaism in Memory of Samuel Sandmel Chico, Calif., 1984, pp. 183-211.

W. Wroth, British Museum Coins 23: Parthia, London, 1903.

(Rolf Strootman)

Originally Published: March 25, 2015

Last Updated: March 25, 2015

Cite this entry:

Rolf Strootman, "SELEUCID ERA," Encyclopædia Iranica, online edition, 2015, available at (accessed on 25 March 2015).