In this story I'm writing, I start in a sword and sandal "age of myth" type setting, but as the centuries press on, it becomes medieval in nature. As even more time passes, there is even some steampunk influence that begins to show up.

My question is this; how long does an era last? What are the key factors in moving on from one era to the next?

(Please note that this is a fantasy world, not an alternate history earth. Like most fantasy worlds, this one draws many parallels to ours however.)

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    $\begingroup$ I think 'eras' are usually defined by historians by some more or less arbitrary events or calender - in any way quite some time AFTER they are actually over. For any people living it will always be a continuous shift (though with varying degrees/speeds of shifting) $\endgroup$
    – Nicolai
    Commented Jun 12, 2017 at 2:40
  • $\begingroup$ Gosh, I hope my answer helps. I am afraid that it won't because eras can be decades or centuries as defined by historians... $\endgroup$ Commented Jun 12, 2017 at 8:04
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    $\begingroup$ Define era and you might get an answer other than "your question doesn't make sense" for 1k lines. $\endgroup$
    – Raditz_35
    Commented Jun 12, 2017 at 11:15
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    $\begingroup$ This would be more appropriate on History S.E. $\endgroup$
    – Vincent
    Commented Jun 12, 2017 at 15:21

7 Answers 7


The first major distinction is between prehistory and history. Basically, history is the timeframe for which we can (attempt to) date events with reasonably good precision and we know the names of at least some important people, usually rulers. Everything earlier is prehistory. By and large, history begins in the 3rd millenium before the common era, in Mesopotamia and Egypt, with the oldest written documents that we can read.

There is no such thing as a universal periodization of history; we the participants to this forum are more familiar with the periodization pertaining to the lineage of civilizations which eventually resulted in the modern western civilization (Europe, the Americas, Australia, parts of Asia, parts of Africa). This is commonly organized as follows:

  • The Antiquity:

    • Preclassical, or deep antiquity: from the earliest document to about the 6th century before the common era.

    Major event: the Battle of Marathon, 490 BCE. The western world separates decisively from the Near East / Middle East.

    • Classical period: from the 6th century before the common era to the 3rd or 4th century of the common era. This is the age of the Greek, Hellenistic and Roman civilizations; it lasted for about one thousand years.

    Major event: the fall of the Western Roman Empire, 476 CE. Western Europe is broken into a multitude of small and weak centers of power.

    • Post-classical antiquity: a brief period between the classical world and the Middle Ages; roughly from the 3rd or 4th century to the 6th century of the common era. In this time the classical world mostly disintegrated and the feudal relationships specific to the Middle Ages were established. The major powers in our lineage were the (Eastern) Roman (aka Byzantine) Empire and the Persian Empire.

Major events: the (Eastern) Roman (aka Byzantine) Empire loses Syria and Egypt to the Arabs. The classical world dies forever.

  • The Middle Ages, from roughly the 6th or 7th to the 14th or 15th century; about 8 or 9 centuries. It covers the time span between the fall of the classical world and the rapid developments of the Renaissance.

    The essential characteristics of the Middle Ages are feudalism and the existence of numerous small centers of power, which were only very loosely structured in larger kingdoms or empires. Another important characteristic of the Middle Ages is that the loyalties of people were to persons and not to countries or institutions; this makes the medieval world very different from the classical antiquity and the modern world; please note that in a story set in the Middle Ages it makes no sense to have patriots (there is no concept of loyalty to a nation, and there is no concept of a nation as a political structure).

Major events: fall of Constantinople to the Ottomans (1453), Columbus reaches the New World (1492), Vasco da Gama reaches India (1498).

  • The Renaissance, a short period from the 14th to the early 17th century; this is a time of rapid developments in culture, science and technology, and of geographical discoveries. This unprecedented developments resulted in the dissolution of the feudal bonds and the emergence of the modern world. The Renaissance begans asynchronously in different parts of Europe; by the late 14th century Italy was in full Renaissance mood, whereas northern regions such as England and the Germanies were still fully medieval.

Major event: the 30 Years War, 1618-1648. Almost western and central European states are involved.

  • The Modern age, usually reckoned to begin with the Peace of Westphalia which ended the 30 Years War. (Sometimes the Renaissance is subsumed as the first part of the Modern age, or as the last part of the Middle Ages.) The major characteristic of this ages is the emergence of sovereign states as the principal actors on the historical stage, and the universal importance of the rule of law. It is usually divided into:

    • The Early Modern period, which saw the first industrial revolution, and
    • The Late Modern period or the age of machines, beginning with the second industrial revolution in the 19th century.

This periodization is made simply in order to make it easier for students to understand historical development. The people actually living in the 6th century did not in any way have a feeling that they were living in a time of transition between the Antiquity and the Middle Ages. The guiding principle of the periodization of history is finding great commonalities, in social structure, culture, economy and so on.

It is important to understand that any periodization of history is specific to a civilization or to a lineage of civilizations; for example, the division between the Renaissance and the Modern age is highly specific to the European civilization and it is completely meaningless to the Oriental civilizations of India, China, Indochina and Japan. For and Indian, or a Chinese, or a Japanese history has different periods specific to the development of their civilizations; for example, in the history of Japan the modern period begins with the Meiji Restoration in the second half of the 19th century.


An "era" is just an artificial distinction made by historians when looking back.

It is not like an average person woke up on Jan 1st, 1493 and said: "oh man, I don't feel Medieval anymore".

History is a continuous flow of events which slowly change the way humans perceive their society. It usually happens that, once in a while, this slow change has a sudden acceleration with an event that is perceived as a cornerstone and is, therefore, easily usable as a reference, like:

  • The deposition of the last western Roman Emperor (for the beginning of the Middle Ages)
  • The discovery of America (for the end of the Middle Ages)
  • The French revolution for the start of the Modern Era

As a rule of thumb, since you have to allow important cultural changes, you have to allow some centuries to flow and, since you are creating your timeline, throw in some major event to mark the change. Revolutions, discoveries, wars... I think human history has quite a set of possibilities to feed your imagination.

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    $\begingroup$ @Jasper Christians weren't routinely being seized and sold into slavery in 1490. The christian kingdoms were advanced onto muslim ones for nearly two centuries by then. Jews were expelled in 1492, but most of muslims remained and weren't expelled until a hundred years after (1609-1614). $\endgroup$
    – Rekesoft
    Commented Jun 12, 2017 at 9:20
  • $\begingroup$ @Rekesoft -- Thank you for the correction. $\endgroup$
    – Jasper
    Commented Jun 12, 2017 at 15:16
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    $\begingroup$ For that matter, even some of the "cornerstone events" are fuzzy. If you look at the fall of the Western Roman Empire, it lasted about a century, and defining Romulus Augustulus as the last emperor (or an emperor at all) is fairly arbitrary. You could make a case that the last emperor was Julius Nepos, or that the empire continued (without an emperor) under Odoacer. $\endgroup$
    – Mark
    Commented Jun 12, 2017 at 18:42

As to "moving on" I think that we can safely break that down into categories. While we might have a certain way of framing an era overall, remember that it can literally be defined by anything (Age of the Flapper! Roman Empire! Bronze Age!)

  • Technology. Different ages are defined by different tech. Bronze Age vs. Steel, that sort of thing. Age of flight, Age of gun powder. In a fantasy setting, it might be something magic-based.
  • Different social structure. The transition to the Renaissance, while you might point to art and such, was made possible by a growing middle class, commoner mobility and merchants and banks running things more often than lords. In America we have the Plantation Era aka Antebellum which ended with the Civil War, and contributed to a different social structure.
  • Rize and Fall of Empires.
  • Big discoveries & development of land. So the Age of Exploration. And in America there was the Western Expansion.
  • Really big wars. War of the Roses. The Civil War. The French Revolution. All of these, at beginning and end changed things.
  • A particularly long-lived ruler. Victorian Age. Edwardian Age.

The main take-away is this: Eras, such as they are, can come down to lots of things, when we look back at them. And they are LAYERED. Different eras can happen at the same time, pertaining to different outlooks! That's something that I think can get lost in world-building--the "Golden Age of Flight" was happening at the same time as the "Age of the Flapper." A film star's death can be called "the end of an era."

Eras are messy things, and they get defined by historians, people who write books and an educational system. They can be small, just decades long--or they can last for centuries. And defining when they begin or end--can be murky. Ask a dozen people when the Renaissance began and Medieval times ended. There are scholars who say there are definite ends and beginnings--but they don't always agree. Like I totally don't agree that 1492 when Columbus discovered America was what ended the Middle Ages. I would say the Renaissance was in full swing by 1492, and that the Age of Discovery that was happening at the same time would not have been possible had we still been in Medieval times. (And speaking of Medieval times--there's like several names for that--the Middle Ages, the Dark Ages, Medieval Times--an era isn't always just known as one thing. That might be confusing to readers, but real life is generally, but not always, a bit weirder and more complicated than fiction).

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    $\begingroup$ Just to make things muddier: name the date delineation between Generation X and Generation Y. I dare you. It's only been 20 to 40 years since it happened, so why haven't we defined that date yet? Should be easy! $\endgroup$ Commented Jun 12, 2017 at 13:55
  • $\begingroup$ @Draco18s I actually think that the more time that goes by, the more likely we are to reach a consensus on the beginning and end of an era. Kinda. Ish. $\endgroup$ Commented Jun 12, 2017 at 17:06
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    $\begingroup$ Sure, ish, maybe. We also still don't even have a name for the Generation X cohort. Unlike Generation Y, which has become "Millennials" (a name I'm good with) although Generation Z isn't expected to attain an identity and thus name for another decade or so (as generally a generation is named by the previous generation). One suggested name so far is "the Internet generation" because they were born after the internet was popular, but I dislike that name (because it makes it sound like they invented or popularized it) and prefer "Digital Native." $\endgroup$ Commented Jun 12, 2017 at 17:17
  • $\begingroup$ @Draco18s Oooh Digital Native. I like that. $\endgroup$ Commented Jun 12, 2017 at 17:31
  • $\begingroup$ It's a shorter version of the original term, "Neo-Digital Native." But yeah, I like it too. Definitely makes the reader/listener go "oh, they grew up online." $\endgroup$ Commented Jun 12, 2017 at 17:33

Based on my favourite fantasy world - The Elder Scrolls - there are 2 types of eras; the first is defined by historians based on events in pre-recorded history which have vague or unknown start times and duration, the second is defined by the government based on significant changes in governance and culture.

For example, the first historic era (Dawn era) is based on the creation of the world by the gods - a religious belief that varies by culture. The second historic era (Merethic era) is based on the oldest evidence of past peoples, which is quite vague and is heavily mythological.

The recorded history eras, which are numbered one to four, are defined by the government of the ruling Empire and has changed each time as a new dynasty comes to rule. The first era was created by the first humans to arrive on the primary continent of Tamriel and based on their creation and domination of the various provinces within the continent. When one dynasty fell (or was toppled) another rose the power, announcing a new era to commemorate the beginning of a new government.

As I said, this is from another fantasy world and not a real example - however I like the way that eras are defined in The Elder Scrolls.

For reference, there's more information here: http://en.uesp.net/wiki/Lore:History


The separation is usually marked by some big event. This is true for history as well as fiction. These events are entirely specific to your world and can be wars, deaths of important figures, something related to religion, famine, earthquakes, rebellions, etc. A famous example is the use of Dynasties.

How long an era lasts depends entirely on the timeframe. If you look at a 200 year period, each era may be 10-60 years and be marked by the high king of XYZ at the time. If you look back 3 billion years, each era is a few hundred million years long.

If and only if you look back far enough that exact dates are no longer relevant or even possible, you can mark the ages by technology, as in bronze age and iron age.

When switching from one era to the next, keep in mind that the new era doesn't usually introduce brand new technology out of nowhere. While cannons and guns have had a major impact during some eras in Eurasian history, at that point the early forms of these weapons had been around for hundreds of years and steadily been improved. Technology that comes out of nowhere and impacts almost everyone's life, is relatively rare. Even the printing press took about 40 years until it had spread all over Europe.

Big rapid changes that happen when moving from one era to the next are usually social in nature, such as an end of slavery, the fall of guilds, etc. But even these don't happen in a vacuum, and require a large set of preconditions.


Era is not a time span. It's a classification of a noun. As to categorize a noun as being different from another noun where the nouns are the same.

We can take "Kings" and define a group of Kings as the Age of Kings, but there were Kings before and after that age. The time span for this age could be based upon facts (i.e. the Age of Kings only includes the children of King Author), or they can be opinion based such as only British Kings.

The problem here is that the time span is different depending upon who you ask, but the classification doesn't change.

So for an Era to have credibility it needs to be endorsed by a credible source. (i.e. the Historian Society of Kings defines the Age of Kings to be between 1200 and 1400).

People argue about when Era's took place all the time, and the importances of the Eras (i.e. is this category important enough to bother classifying those things in writing).

Since an Era is not a time span. It does not start, end or transition to other Eras. We just don't classify those things after X as being part of the another Era.

I could say that the Era of the Dodo Bird ended in 1750 when it went extinct, but if someone found one alive in the forest does this change their Era? No, because Era doesn't define a time span. We would just say "this new discovery belongs to the Dodo Bird Era" and leave it at that.


The Betamax era lasted 45 years.

The Paleozoic era lasted 288,830,000 years.

So basically as long as you like, depending what you think is significant.

  • $\begingroup$ That’s more of a comment than an Answer. Take a look at other answer posts and comments on this question! Maybe use this as the introduction and go on to offer advice on choosing or figuring out just what is significant, and gudelines for how long each takes? $\endgroup$
    – JDługosz
    Commented Jun 13, 2017 at 12:12

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