Chronology

Chronology (Gr., 'time-reckoning'), the science of time, especially in regard to (1) the occurrence, recurrence, and succession of events, or (2) the duration of periods and cycles. The immense array of facts with which chronology is occupied may be distributed under two great heads—Mathematical or Astronomical Chronology, and Technical or Political Chronology. The former deals with celestial phenomena, their order and the laws of their occurrence and duration, events outside of man's sphere or influence. The latter branch deals with the whole history of our race upon this planet; and by the selection of certain fixed points in time called Epochs, refers to each of them the succession of social and political events occurring in the period immediately following it, and reckoned from it, which we term its Era. As soon as the elements of mathematical chronology were understood, political chronology had solid ground to build upon, and assume a systematic form: then a science of history became possible. A 'year,' for example, seems now an easy and natural unit of time-measurement; but for long ages the only idea suggested by the word was that of a vague, intangible period. So late even as 450 B.C. we find Herodotus expressing duration of time by the phrase 'three generations' (= a century) or 'five generations;' and in all languages we find 'six summers' or 'sixty winters' instead of so many years.

In the rudimentary stage of chronology, a nation referred its history to the lifetime of some central figure, such as the king, the tribal chieftain, &c.; of which custom we actually find a survival in our system of dating acts of parliament. The priestess of Juno at Argos was another instance; and in the Roman and Athenian republics, where the chief-magistrates were chosen annually, an event was conveniently said to have occurred 'when Plancus was consul,' or 'in the archonship of Kallixenos.' Similar to the Roman consul and the Athenian archon was the Assyrian limu or 'eponym,' from whose name Babylonian and Assyrian documents were dated far more frequently than from that of the reigning king. Such a chronology, however, could only be of use within narrow limits both of time and place; and at all the great centres of civilisation we find that as men's historical views widened with the national growth, they began to invent eras, some from national or political motives, others ecclesiastical, and a few scientific. Progress in astronomy, such as we find in China and Babylonia at the dawn of history, was of notable service at this stage. To the Accadians of the latter country indeed both astronomical and political chronology owe a lasting debt of gratitude. The Chinese, no doubt, show a time computation which is apparently prehistoric, and their recorded eclipse observations prove a chronology of at least four thousand seven hundred years' duration; but if they did adopt a year measurement equivalent to our Julian system some 2000 B.C., it is certain they have exerted no influence on European civilisation compared with that of the Accadians of Babylonia, or ancient Chaldeans as they used to be named. Fairly accurate chronology in ancient Babylon begins with Sargon I., king of Agade, 3800 B.C. The earliest authentic date is that inscribed on the foundation stone of the temple to the sun-god at Sippara by Naram-Sin, son of Sargon. This was dug up by Nabonidus, who began to reign over Babylon about 554 B.C., and who says that Naram-Sin reigned 3200 years before his time, thus giving a total of 3754 years B.C. as the date of his building of the temple. Thus by the year 4000 B.C. the nation had attained to considerable advance in literature, science, and art. Much of the greatness of Babylonia, foremost in culture for centuries, was afterwards reflected in Assyria, who inherited her civilisation and learning, as in a lesser degree also did Israel. Berossus gives a list of dynasties of 120 saroi, or 432,000 years before the Deluge, and of eight dynasties after it, and Ptolemy's canon in the Almagest gives the seventh dynasty in full from Nabonassar (747 B.C.) to Sinêladanos (Assur-bani-pal, 668-626). From about 2330 B.C. they used a regular calendar, with a week of seven days, and a year of twelve months, named after the zodiacal signs. Their year was of three hundred and sixty days, which probably suggested that division of all circles into degrees which we have derived from them. In astronomical chronology they had cycles of sixty years, six hundred years, and the sar (= 3600 years)—the factor sixty running through all their arithmetic. The great Babylonian work on astronomy and astrology was the 'Observations of Bel,' compiled at Accad for Sargon, and translated into Greek by Berossus. It was mostly a record of eclipses of the sun and moon, conjunctions and phases of Venus and Mars, the time of the new year, the names of the zodiacal signs and the divisions of the year. The famous Assyrian eponym canon, discovered by Sir Henry Rawlinson in 1862, fixes definitely for us the chronology of Assyria from 1330 B.C. to about 620 B.C.; but a fairly accurate list of kings can be made out up to perhaps 1700 B.C. Thus continuing that early pre-Semitic civilisation, the more warlike Assyrians furnish many dates of importance—e.g. 720 B.C., Sargon conquered Arabia and Syria, levying contributions from Cyprus; 705 B.C., Sennacherib conquered Phoenicia and Egypt, carrying away two hundred thousand Jews; 681 B.C., building of the great palace at Nineveh, where afterwards, during the golden age of the Assyrian empire, ruled great Assur-bani-pal (long called Sardanapalus), the brilliant patron of art and letters. The discovery, in our time, of his national library almost compensates the literary world for the loss of that of Alexandria. See BABYLONIA, ASSYRIA.

To the Chaldean astronomy we owe the Saros, a cycle of two hundred and twenty-three lunations, which is still of signal importance in calculating eclipses. To it also is due the era of Nabonassar, one of the most famous in the annals of chronology, the basis of all the computations of Ptolemy, and frequently referred to both by historical and astronomical writers—e.g. in connection both with Alexander the Great and Aristotle. From its epoch, 26th February 747 B.C., it maintained its ground till after the commencement of the vulgar era. In the same century, singularly enough, occur the epochs of two other eras which, though of less note in astronomical chronology, are much more familiar to historical readers—viz. the Greek era of the Olympiads, reckoned from 1st July 776 B.C., and the Roman era of the Founding of the City (A.U.C.) from 22d April 753 B.C. The public games at Olympia formed an essential part of the national life to a Greek; and thus we find Xenophon refer an event to the year when Eubotas of Cyrene won the foot-race, just as in some parts of England a man will be heard saying 'Ah! that was the year Friar Tuck won the Derby!' The Olympic Games were of unknown antiquity, but the era or first Olympiad dates from the year when Corœbus was victor. Extending over a period of four years, the Olympiad (q.v.) was really a small cycle; thus the year 729 B.C. is expressed in Greek chronology as the third year of the twelfth Olympiad. The Latin epoch, the Founding of Rome, is not so accurately known as that of the Greeks; but the date assigned by Varro (753 B.C.) was accepted by Cicero and Pliny, and has been generally adopted by modern historians. Cato's date (751 B.C.) deserves note, from its use both by Livy and Dionysius of Halicarnassus: 750 was that of Polybius. Nor must we forget that all Latin writers, and many Greeks also, dated an event by naming the Roman consuls of the year. Under the empire, in 312 A.D., Constantine introduced the cycle of fifteen years, called Indiction (q.v.), of which, as an official mode of computation, there still remained some survival in France at the end of the 15th century. The old Roman era, however, as well as the Grecian, maintained some footing till after the birth of Christ; and the latter has even been traced to 440 A.D. = 304th Olympiad.

The Greeks had the honour of inventing the Metonic cycle (commencing 15th July 432 B.C.) of 235 lunations = 19 years, and also the Calippic of 76 years. Like the Chaldean saros, both of these cycles were used to predict new moons, eclipses, &c.

Of the Hindu or Egyptian eras there is little that affects the science of chronology. The antiquity of the Indian epics is a question purely literary; and the only epochs to record here are the descent of the Aryans on the Punjab about 2000 B.C.; the Council of 543 B.C., which inaugurated the Buddhist era, and that of 309 B.C., when Buddhism (q.v.) became the state religion. The Indian chronology has some affinity to the Chinese; and a singular refinement in their mode of computing time was their use of the sidereal year—i.e. reckoning by the return of a meridian to the same star (see YEAR). The Egyptians, on the contrary, though their year began with the rising of the star Sirius, called a year 365 days exactly, and were, therefore, compelled to use a cycle of 1461 years (= $4\; \backslash times\; 365\; +\; 1$), a most cumbersome adjustment, though simple. The week of seven days was from earliest time adopted by the Brahmins in India, and the ancient Egyptians, as well as by the Accad settlers of Babylonia already referred to.

The Jewish chronology is unimportant except from its relation to religious matters, and scarcely affords examples of any era, since sacred chronology, as it is called, is only partially based upon the Pentateuch. What knowledge of astronomical chronology the Jews had was derived from the ancient Chaldeans through the Assyrians, and their calendar was mainly Egyptian. Their year, like that of the ancient Greeks and modern Turks, consisted of twelve months of alternately thirty and twenty-nine days (or twenty-nine and a half on an average—i.e. a lunation), with an intercalary month once in three years, and sometimes once in two. One peculiarity of the Jewish calendar was that they divided their year into six seasons—seed-time, winter, cold season, harvest, summer, and hot season—an arrangement due probably to their climatic surroundings. Leaving Egypt circa 1320 B.C. (so Bunsen, following Eratosthenes; others give 1330), the Jews showed some signs of national vigour in the 12th century B.C. on the decay of the Egyptian empire, and their history reached a short culmination in the reign of Solomon. When split into two small kingdoms they soon found that, although assisted by Syria and their more civilised neighbours the confederation of the Phœnician cities, they were of but little avail against the might of Assyria. By the siege of Samaria in 721 B.C., and that of Jerusalem in 587 B.C., the little kingdoms of Israel and Judah were successively overthrown, and the Jewish nation finally shattered. Having no national chronology, the Jews who returned to Palestine are found using the Macedonian era, which dates from 311 B.C., the reign of Selencus, one of the successors of Alexander the Great. This they did in common with the Syrians and Greeks all round the Levant, and reckoned by it till the 15th century, as some Arabians are said still to do. At present the Jews, as also the Freemasons, profess to date their calendar from the 'Creation,' 3760 years B.C.

Sacred chronology, or that of Scripture, is an attempt to harmonise the succession of events recorded in the Old Testament, especially with reference to the semi-traditional or prehistoric period preceding the Exodus. There are three accounts—the Jewish, the Samaritan, and the Greek Septuagint—and their discrepancies, though referring to the same periods and succession of events, are hopelessly irreconcilable. Sacred chronology divides all time before the birth of Jesus Christ into three great periods (as in the following table); and as to the first all the texts are at variance, while in the middle period the Septuagint agrees with the Samaritan, but both differ from the Jewish reckoning by 650 years :

The three authorities, therefore, entirely disagree as to the total period. To complicate the confusion, all those results are given differently by different interpreters; and no less than over two hundred varying computations have been made as to the date of the creation, ranging from 3483 years to 6984. The familiar date in English books was 4004, following Archbishop Usher's reckoning. At last it became clear through science that man's duty is to strive to interpret nature, and to shrink from assigning any limit to her works as to either beginning or ending. The Newtonian chronology was an attempt (published posthumously be it remembered) to rectify some of the discrepancies in sacred and profane history, by combining a critical examination of authors with astronomical calculations. For example, the famous date of the Argonautic expedition was, by an ingenious application of the precession of the equinoxes, assigned by Newton to forty-three years after the death of Solomon, or 937 B.C. (Hales), a date utterly inadmissible. For the expedition, if indeed it ever took place, must have preceded the siege of Troy, which is ascribed to 1184 B.C.

The Hegira (Hedjrah) or epoch of the Moslem era is dated Friday, 15th July 622, the New-year's Day of the Arabian year, or, as others say, from the 16th. The Mohammedan year being strictly lunar—from the primitive reckoning by months instead of years—the calendar requires several adjustments from time to time by means of tables arranged according to cycles of thirty years, of which nineteen have 354 days and the others 355. The principal festivals of the Moslems are the New-year, the birth of the Prophet, the taking of Constantinople, and the Grand Bairam (q. v.).

From these minor systems of chronology we at once pass to that of our present era, which, though begun as it were accidentally, unenforced by the authority and command of emperors, kings, or councils, seems destined soon to assert universal predominance. The Christian era (or 'vulgar era' as older writers termed it) has its epoch or point of departure determined by the Gregorian rule—viz. : 'The years are denominated as years current from the midnight between the 31st December and the 1st of January immediately subsequent to the birth of Christ, according to the chronological determination of the event by Dionysius Exiguus.' Now as Dionysius, the obscure author of this chronological scheme, lived in the beginning of the 6th century, there was no exact determination of the epoch; and it cannot therefore be so precisely formulated as other eras of less importance. It is generally agreed that the beginning of the era should have been fixed from two to four years earlier. Another point not generally noted is that the correction of our calendar by Pope Gregory itself wanted correction; because instead of ten days the papal bull should have enjoined an omission of twelve. His Holiness or some adviser proposed the Council of Nice as their starting-point in estimating the error already made, and reckoned therefore from 1st January 325 A.D. instead of 1st January 1 A.D. The only wonder is that his astronomers assented. It may further be pointed out that the papal reformation itself is by no means the best that could have been devised; and that long before that date, in 1079 A.D., Omar Khayyám, the Persian astronomer-poet, proposed a scheme for adjusting years and days not only more exactly, but much more simply. Omar's rule, shortly, was: (1) Intercalate a day every fourth year, but (2) intercalate during the thirty-third year instead of the thirty-second. By this scheme five thousand years must elapse before a further correction is made—viz. of one day, whereas by Gregory's rule a correction of three days is necessary within four thousand years. In this connection may be noted the extremely ingenious mode by which the new style was adopted in Sweden—viz. by deciding to have no leap-years between 1696 and 1744.

From the mode of fixing the epoch of the existing era as indicated above, it is manifest that, since there is no 0 A.D. and no 0 B.C., we must diminish the sum of the nominal years B.C. and A.D. by unity to find the interval. Thus the years between 1st January 753 B.C. and 1st January 1888 A.D. are not 2641 but 2640. The epoch 1st January 1 A.D. was first, as we have seen, established by measuring backwards according to the estimate of Dionysius Exiguus in 527 A.D.; and when measured forwards from other epochs we find that our era dates from 1st January of the fourth year of the 194th Olympiad = 753 A.U.C. = 4714 of the Julian period.

That brings our subject to an era, which, theoretically at least, is the most important in the science of chronology. The epoch of our existing era is not well suited for technical purposes, as all astronomers and chronologists allow, because the birth of Christ is too recent an event; thus enhancing the difficulty of fixing the relation between the different systems, and of expressing a date or period of one era exactly in terms of another. Therefore, just as Fahrenheit chose for his zero a mark thirty-two degrees below freezing-point, in order to avoid negative measurements, so the Julian period had its epoch fixed to 1st January 4713 B.C., a point of time antecedent to all other epochs, in order that its era should be a convenient standard to which all other chronological systems can be differentially referred. Its length is 7980 Julian or Metonic years, the product of 28 (Solar period), 19 (Lunar period), and 15 (Indiction), and thus constitutes a great cycle embracing and unifying three subordinate cycles which are constantly referred to; because the year 4713 B.C. is the most recent date when those important periods began exactly all together. With the further development of technical chronology, and a more scientific treatment of history and ethnology, we may look for a much wider use and appreciation of the Julian period as a cycle comprehending all really historic time, and fulfilling certain astronomical conditions of the first importance. When the year of the Julian period is known, the corresponding date for any of the subordinate cycles is easily found, and conversely. We subjoin a table for the comparison of some selected dates:

EPOCHS AND LEADING EVENTS IN CHRONOLOGY REFERRED TO THE JULIAN PERIOD.

The Julian period or cycle in its modern form was proposed by Joseph Scaliger, but the Greeks of Constantinople appear to be the authors of it. Its exact epoch is noon of 1st January 4713 B.C. for the meridian of Alexandria, which was chosen as being that to which Ptolemy had referred the era of Nabonassar already discussed. Scaliger has the best right to the title of father of chronology, often given to Eratosthenes.

The astronomer Laplace in recent times proposed another universal era not so practical in its bearing on political chronology. He calculated that about 4000 years B.C. the major axis of the earth's orbit coincided with the line of the equinoxes, and that in 1250 A.D. they were at right angles. In the latter year, therefore, he proposed to fix the universal epoch whence the whole world should reckon, the vernal equinox to be the first day of the first year, when the solar perigee coincided with the summer solstice. With Laplace's estimate may be compared the dates of coincidence with the solar perigee which are tabulated above.

There are many other instances of astronomical chronology overlapping and influencing political chronology. Thus, by reckoning back we are able to identify the time and place of some remarkable eclipses, such as that of Thales (see in table above), which caused the suspension of a battle between the Medes and Persians. Another striking verification was by that of Larissa, the Ninroud of Mr Layard. Scottish history furnishes another recent instance. We read that when King Haco sailed from Bergen with his Norse fleet to punish the king of Scotland, he put in at Ronaldsvoe in Orkney, which was then subject to him, and that there the sun appeared as a thin bright ring. Sir David Brewster found by computation that there was an annular eclipse of the sun passing over Orkney on 5th August 1263, about one o'clock. Two months afterwards Haco was defeated at Largs, and Alexander annexed the Hebrides to Scotland. 'The ring at Ronaldsvoe was an evil portent.' Such verifications in chronology are dependent on the testimony of contemporary writers. Other valuable information has been derived from coins, medals, monuments, and inscriptions.

To treat adequately many of the important ramifications of our subject is here impossible, and we have therefore only passed under review the main features of the science as a whole. One department, however, of political or technical chronology deserves special attention from its interest to antiquaries and lawyers as well as to historians—viz. the method of assigning events to their respective years, or fixing their dates as it is called, either by verifying in cases of doubt, or reconciling and correcting in cases of discrepancy, inconsistency, and contradiction. How, for example, can the following dates be accounted for—all printed in the same month of the same year, 1705? In the London Gazette of 13th February is given a translation of which there is an abridgment in the Edinburgh Courant of the 19th, yet the original passage is in the Amsterdam Gazette, dated 22d February.

The first cause of such discrepancies is the difference of styles (see CALENDAR), which occasions seeming blunders of ten, eleven, or twelve days, according to the century. As 170 years elapsed before England adopted the new style, the chief Roman Catholic countries being followed by Poland (1586), Hungary (1587), Strasburg (1682), German Protestant States (1700), and Tuscany (1749 or 1751), all in different years, there was ample room left for innumerable discrepancies as to dates.

Besides differing in the style—i.e. Julian or Gregorian—two nations frequently began the year at different times. A Scottish writer assigned the execution of Charles I. to 1649, and his English contemporary to 1648, though both agreeing as to the month and day; because in Scotland the year began with the 1st of January, as it had done since 1600, and in England the 25th March was still New-year's Day. Throughout Europe there was much variation in this respect, not only between one country and another, but even in the same country as between one time and another, as well as between its different provinces at the same time. The most common New-year's Days were these four—(a) 25th December; (b) 25th March; (c) Easter; (d) 1st January. Thus England used both the first and second from the 6th century to 1066; the fourth till 1155; then the second till the day after 31st December 1751, which was called 1st January 1752. Scotland used the second till 1599, when the day after 31st December 1599 was called 1st January 1600. France under Charlemagne used the first, and afterwards also the third and second till 1563. The 25th March was originally chosen by Dionysius Exiguus, the author of our present era, as being the Annunciation—exactly nine months before Christmas. A survival of its use in England appears in the annual Treasury accounts, and in preserving Lady-day as a quarter-day.

In many English documents before 2d September 1752, owing to the delay in accepting the Gregorian reformation, we find a date thus, 12th February 170⁶ or 1706-7, meaning 1706 if the year begin on 25th March, or 1707 if it begin on the 1st of January. This ambiguity of course only applies to days falling between 1st January and 24th March.

A third cause of error or uncertainty arose from dating ancient writings not only by saints' days and church festivals, but by some Latin psalm or other portion of the service which the clergy (who of course were generally the clerks) associated with the day in question. Thus we find as a date (15th century) 'the Wednesday next after Deus qui errantibus,' and (in 1610) 'the Sunday on which the church sings Reddite quæ sunt Cæsaris Cæsari.' A Scottish parliament of 1318 met at Scone 'on the Sunday next after the feast of St Andrew the Apostle;' and an English one of 1399 is only dated in a contemporary account by the phrase 'on Monday the feast of St Faith the Virgin.'

A special complication arose from dating documents, and especially all state papers, by the year of the king's reign, as already referred to. Even in Rymer's Fœdera, a work of the highest importance in English chronology, we find that from this cause many of the public papers from Richard I. to Edward IV. are misdated by a whole year. Our early sovereigns dated their reign from the coronation, and the writers of history frequently assumed that every king's succession was officially dated from the day of his predecessor's death. In the case of popes of Rome, moreover, scarcely any two of them in immediate succession, until recent times, dated or computed on the same principle; and some of them vary their methods even within their own reigns. In this connection may be noted a clerical error in the Scottish records of David II., where after his return from captivity every date of his reign is given one year short. Frequently too in public documents, both English and Scottish, we read 'King Henry,' 'King Edward,' 'King Robert,' or 'King James,' without further qualification; so that for purposes of chronology we must study the penmanship, the style and wording, the seal, and above all the names of the persons enumerated. Even then the antiquary or historian is sometimes unable to reduce the date of an instrument or letter within a narrower range than fifty or even a hundred years.

A reference to contemporary history will sometimes fix the date. For example, there are two acts in the Scottish statute-book which are thus dated—one, 'at Aberdeen in Lent next after the coming in Scotland of Vivian the Legate of the Apostolic See;' the other, at Stirling, 'on the Monday next before the feast of St Margaret the Maiden next after the first coronation of Philip king of the French.' From these data we can assign their dates as 1177 and 1180 respectively.

Bibliography.—Scaliger's De Emendatione Temporum (1583); Usher's Annales V. and N. Testamenti (1650); Sir I. Newton's Chronology Amended (1728); L'Art de Vérifier les Dates (1818-31); Herschel's Astronomy; Ideler's Lehrbuch (1831); Clinton's Fasti, &c.; Chronology of History, by Sir Harris Nicolas (1838); Brinckmann's Handbuch (1882); Woodward and Cates's Encyclopaedia of Chronology (1872); Whitworth's Churchman's Almanac from 1201 to 2000 (1883); Brockmann's System der Chronologie (1883); James C. Macdonald's Chronologies and Calendars (1897).