Periodization

Periodization is the process of categorizing the past into discrete, quantified, named blocks of time in order to facilitate the study and analysis of history. This results in descriptive abstractions that provide convenient terms for periods of time with relatively stable characteristics.

To the extent that history is continuous and cannot be generalized, all systems of periodization are arbitrary. Moreover, determining the precise beginning and ending to any period is also a matter of arbitrary decisions. Eventually, periodizing labels are a reflection of very particular cultural and geographical perspectives, as well as specific subfields or themes of history (e.g., military history, social history, political history, intellectual history, cultural history, etc.).

Consequently, not only do periodizing blocks inevitably overlap, but they also often seemingly conflict with or contradict one another. Some have a cultural usage (the Gilded Age), others refer to prominent historical events (the interwar years: 1918–1939), yet others are defined by decimal numbering systems (the 1960s, the 17th century). Other periods are named after influential individuals whose impact may or may not have reached beyond certain geographic regions (the Victorian Era, the Edwardian Era, the Napoleonic Era).

Western Historical Periods

The common general split between prehistory (before written history), ancient history, Middle Ages, modern history, and contemporary history (history within the living memory) is a Western division of the largest blocks of time agreed upon by Western historians and representing the Western point of view. For example, the history of Asia or Africa cannot be neatly categorized following these periods.

However, even within this largely accepted division, the perspective of specific national developments and experiences often divides Western historians, as some periodizing labels will be applicable only to particular regions.

This is especially true of labels derived from individuals or ruling dynasties, such as the Jacksonian Era in the United States, or the Merovingian Period in France. Cultural terms may also have a limited, even if larger, reach. For example, the concept of the Romantic period is largely meaningless outside of Europe and European-influenced cultures; even within those areas, different European regions may mark the beginning and the ending points of Romanticism differently. Likewise, the 1960s, although technically applicable to anywhere in the world according to Common Era numbering, has a certain set of specific cultural connotations in certain countries, including sexual revolution, counterculture, or youth rebellion. However, those never emerged in certain regions (e.g., in Spain under Francisco Franco’s authoritarian regime). Some historians have also noted that the 1960s, as a descriptive historical period, actually began in the late 1950s and ended in the early 1970s, because the cultural and economic conditions that define the meaning of the period dominated longer than the actual decade of the 1960s.

Periodization in World History: How Many Eras Are There?

While world history (also referred to as global history or transnational history) emerged as a distinct academic field of historical study in the 1980s in order to examine history from a global perspective rather than a solely national perspective of investigation, it still struggles with an inherently Western periodization. The common splits used when designing comprehensive college-level world history courses (and thus also used in history textbooks that are usually divided into volumes covering pre-modern and modern eras) are still a result of certain historical developments presented from the perspective of the Western world and particular national experiences. However, even the split between pre-modern and modern eras is problematic because it is complicated by the question of how history educators, textbook authors, and publishers decide to categorize what is known as the early modern era, which is traditionally a period between Renaissance and the end of the Age of Enlightenment. In the end, whether the early modern era is included in the first or the second part of a world history course frequently offered in U.S. colleges is a subjective decision of history educators. As a result, the same questions and choices apply to history textbooks written and published for the U.S. audience.

World Historians use a thematic approach to identify common patterns that emerge across all cultures, with two major focal points: integration (how processes of world history have drawn people of the world together) and difference (how patterns of world history reveal the diversity of the human experiences). The periodization of world history, as imperfect and biased as it is, serves as a way to organize and systematize knowledge. Without it, history would be nothing more than scattered events without a framework designed to help us understand the past.

World History courses regularly break the subject up into two major periods – one ancient, the other modern – separated by an interlude we call, appropriately for this periodization, the “middle ages,” a time between the two key times in human history. Boston College historian David Northrup proposed two major movements through which we can understand changes occurring throughout world history. The ancient phase of human development was characterized by the divergence of human groups into different geographies, languages, and cultures. The modern era was dominated by the convergence of human societies into the global and globalizing culture of our own time. As humans learned agriculture and began to develop cities, governments, cultures, and languages, their distinct geographic, economic, and strategic situations influenced their development, resulting in diverse cultural patterns impacted by place and time; that is the story of early human history. Modern history has been an era of intercultural contact, borrowing, immigration, and mixing that became gradually more prevalent. Our history for the last 1000 years has become one of greater cultural convergence in which we have come to share more than we differ.

Splitting the history of the world into two main ages (rather than three or four or a dozen) is also a product of the way that educational institutions divide their course offerings. Most post-secondary schools in the U.S. divide their school year into semesters, which most lends itself to dividing a history survey into two parts. Schools that operate on a quarter system (three terms during the regular school year) will often divide the World History survey into three big eras, not two, for the same reason.

Calendars and Writing History

Methods of timekeeping can be reconstructed for the prehistoric period from at least the Neolithic period. The natural units for timekeeping used by most historical societies are the day, the solar year, and the lunar cycle. The first recorded calendars date to the Bronze Age and include the Egyptian and Sumerian calendars. A larger number of calendar systems of the Ancient Near East became accessible in the Iron Age and were based on the Babylonian calendar. One of these was calendar of the Persian Empire, which in turn gave rise to the Zoroastrian calendar, as well as the Hebrew calendar.

A great number of Hellenic calendars were developed in Classical Greece and influenced calendars outside of the immediate sphere of Greek influence. These gave rise to the various Hindu calendars, as well as to the ancient Roman calendar, which contained very ancient remnants of a pre-Etruscan ten-month solar year. The Roman calendar was reformed by Julius Caesar in 45 BCE. The Julian calendar was no longer dependent on the observation of the new moon, but simply followed an algorithm of introducing a leap day every four years. This created a dissociation of the calendar month from the lunation. The Gregorian calendar was introduced as a refinement of the Julian calendar in 1582 and is today in worldwide use as the de facto calendar for secular purposes.

Despite various calendars used across millennia, cultures, and geographical regions, Western historical scholarship has unified the standards of determining dates based on the dominant Gregorian calendar. Regardless of what historical period or geographical areas Western historians investigate and write about, they adjust dates from the original timekeeping system to the Gregorian calendar. Occasionally, some historians decide to use both dates: the dates recorded under the original calendar used, and the date adjusted to the Gregorian calendar, easily recognizable to the Western student of history.

Julian Calendar

The old Roman year had 304 days divided into ten months, beginning with March. However, the ancient historian, Livy, gave credit to the second ancient Roman king, Numa Pompilious, for devising a calendar of twelve months. The extra months Ianuarius and Februarius had been invented, supposedly by Numa Pompilious, as stop-gaps. Julius Caesar realized that the system had become inoperable, so he effected drastic changes in the year of his third consulship. The New Year in 709 AUC (ab urbe condita—year from the founding of the City of Rome) began on January first and ran over 365 days until December 31. Further adjustments were made under Augustus, who introduced the concept of the leap year in 737 AUC (4 CE). The resultant Julian calendar remained in almost universal use in Europe until 1582. Marcus Terentius Varro introduced the Ab urbe condita epoch, assuming a foundation of Rome in 753 BCE. The system remained in use during the early medieval period until the widespread adoption of the Dionysian era in the Carolingian period. The seven-day week has a tradition reaching back to the Ancient Near East, but the introduction of the planetary week, which remains in modern use, dates to the Roman Empire period.

Gregorian Calendar

The Gregorian calendar, also called the Western calendar and the Christian calendar, is internationally the most widely used civil calendar today. It is named after Pope Gregory XIII, who introduced it in October, 1582. The calendar was a refinement to the Julian calendar, amounting to a 0.002% correction in the length of the year. The motivation for the reform was to stop the drift of the calendar with respect to the equinoxes and solstices—particularly the vernal equinox, which set the date for Easter celebrations. Transition to the Gregorian calendar would restore the holiday to the time of the year in which it was celebrated when introduced by the early Church. In an unprecedented display of religious and cultural power, the Church achieved this reset by deleting 10 days from the month of October, 1582 — the pope ordered that the day after October 4, 1582 was to be October 15, 1582, and so it was. The reform was adopted initially by the Catholic countries of Europe. Protestants and Eastern Orthodox countries continued to use the traditional Julian calendar, and eventually adopted the Gregorian reform for the sake of convenience in international trade. (By the time that Great Britain and its colonies adopted the new calendar, the reset required the deletion of 11 days instead of the original 10.) The last European country to adopt the reform was Greece in 1923.

Calendars Outside of Europe

While the European Gregorian calendar eventually dominated the world and historiography, a number of other calendars have shaped timekeeping systems that are still influential in some regions of the world.

The Islamic calendar determines the first year in 622 CE, during which the emigration of Muhammad from Mecca to Medina, known as the Hijra, occurred. It is used to date events in many Muslim countries (concurrently with the Gregorian calendar), and is used by Muslims everywhere to determine the proper days on which to observe and celebrate Islamic religious practices (e.g., fasting), holidays, and festivals.

Various Hindu calendars developed in the medieval period with Gupta era astronomy as their common basis. Some of the more prominent regional Hindu calendars include the Nepali calendar, Assamese calendar, Bengali calendar, Malayalam calendar, Tamil calendar, the Vikrama Samvat (used in Northern India), and Shalivahana calendar. The common feature of all regional Hindu calendars is that the names of the twelve months are the same (because the names are based in Sanskrit) although the spelling and pronunciation have come to vary slightly from region to region over thousands of years. The month that starts the year also varies from region to region. The Buddhist calendar and the traditional lunisolar calendars of Cambodia, Laos, Myanmar, Sri Lanka, and Thailand are also based on an older version of the Hindu calendar.

Of all the ancient calendar systems, the Mayan and other Mesoamerican systems are the most complex. The Mayan calendar had two years, the 260-day Sacred Round, or tzolkin, and the 365-day Vague Year, or haab. The essentials of the Mayan calendar are based upon a system that was in common use throughout the region, dating back to at least the fifth century BCE. It shares many aspects with calendars employed by other earlier Mesoamerican civilizations, such as the Zapotec and Olmec, and contemporary or later ones, such as the Mixtec and Aztec calendars. The Mayan calendar is still used in many modern communities in the Guatemalan highlands, Veracruz, Oaxaca and Chiapas, Mexico.

Anno Domini v. Common Era

The terms anno Domini (AD) and before Christ (BC) are used to label or number years in the Julian and Gregorian calendars. The term anno Domini is Medieval Latin, which means in the year of the Lord, but is often translated as in the year of our Lord. It is occasionally set out more fully as anno Domini nostri Iesu (or Jesu Christi )(“in the year of Our Lord Jesus Christ”). Dionysius Exiguus (Dennis the Humble) of Scythia Minor introduced the AD system in AD 525, counting the years since the birth of Christ. (In later centuries, people discovered an arithmetic error in his calculation, which was off by between four to six years.) This calendar era is based on the traditionally recognized year of the conception or birth of Jesus of Nazareth, with AD counting years after the start of this epoch and BC denoting years before the start of the era. There is no year zero in this scheme, so the year AD 1 immediately follows the year 1 BC. This dating system was devised in 525, but was not widely used until after 800.

A calendar era that is often used as an alternative naming of the anno Domini is Common Era or Current Era, abbreviated CE. The system uses BCE as an abbreviation for “before the Common (or Current) Era.” The CE/BCE designation uses the same numeric values as the AD/BC system so the two notations (CE/BCE and AD/BC) are numerically equivalent. The expression “Common Era” can be found as early as 1708 in English and traced back to Latin usage among European Christians to 1615, as vulgaris aerae, and to 1635 in English as Vulgar Era.

Since the later 20th century, the use of CE and BCE have been popularized in academic and scientific publications, and more generally by authors and publishers, mostly for reason of inclusivity and pragmatism. Firstly, authors have sought to emphasize secularism or sensitivity to non-Christians, because the C.E./B.C.E. system does not explicitly make use of religious titles for Jesus, such as “Christ” and Dominus (“Lord”), which are used in the BC/AD notation, nor does it give implicit expression to the Christian creed that Jesus is the Christ.

While both systems are thus an accepted standard, the CE/BCE system is more neutral and inclusive of a non-Christian perspective; the latter simply recognizes that it is a common system regardless of religious identity. A second, more minor reason is that Dionysius Exiguus’ erred in his calculation. Assuming the Christian gospels are accurate, the person called Jesus would have been born around 4-6 BCE, which would create something of a confusing contradiction — someone was born 4 to 6 years before he was born. Finally, even if everyone readily accepted a Christian-centered calendar system, there exist multiple Christian dating systems besides the Western BC/AD one. Ethiopian Christianity, for example, holds that the Jesus was born 7 years before Western Christianity says that he was born.

“Common” simply recognizes that there is a convenient, widely-used numbering system whose usefulness is independent of accuracy or religious differences.