When did humans start numbering years?

Question

When did humans start to keep track of years with unique identifiers for each year?

I assume that the realization that seasons were cyclic came first, and that at some point we decided to call each cycle a year (I assume this happened before the discovery of how the solar system worked, since it's easier to notice season cycles than rotations around the sun). I assume it was at some later point that we decided to give each of those years a unique identifier (e.g. number) to help keep track of things.

My questions is: when was that "later point"? When did we start "numbering" the years to keep track of them? Who did it first? How did they do it (arbitrary number, years since notable event, ..?)

Also, when did a large portion of a population become aware of this (the numbering)? i.e. if you ask pretty much anybody today they'll be able to tell you what year it is, no matter their walks of life. But I guess that when people first started numbering years it was most useful to certain members of the population and inconsequential for others, therefore some people might have been unaffected and unaware of the current year.

Answer 1

When did humans start to keep track of years with unique identifiers for each year? [...]

My questions is: when was that "later point"? When did we start "numbering" the years to keep track of them? Who did it first? [...]

Also, when did a large portion of a population become aware of this (the numbering)?

It'll probably be impossible to know. Time tracking pre-dates written history, so it's basically anyone's guess when it actually started or when populations became generally aware of what the current date was.

I assume that the realization that seasons were cyclic came first, and that at some point we decided to call each cycle a year

That actually depends on the civilization. For agricultural ones, you might be right. For more ocean oriented ones, the lunar calendar makes sense too. Some lunar calendars are still in use today. The earliest known calendar is lunar and some of its ramifications (12 month cycles, 2*12 hours in a day, 60 minutes in an hour, etc.) are still with us today.

How did they do it (arbitrary number, years since notable event, ..?)

That, historians actually know a bit more on, at least insofar as recorded history is concerned. Pre-BCE, Regnal years seem to have been common. There were also some early calendars with different epochal dates. Events got recorded in these various systems in recorded history, and historians are able to produce chronological tables, like this Babylonian Chronology for instance.

Answer 2

When did humans start to keep track of years with unique identifiers for each year ?

There are two possible ways of approaching this question, depending on what exactly it is you are actually asking :

1. When did humans start to keep track of years with unique identifiers for each year ?

Two random examples:

• The Greek philosopher Plato relates in two of his famous Dialogues a conversation between the Athenian statesman Solon (about 600 BCE) and a certain Egyptian priest whom Plutarch would later identify as Sonchis of Sais, wherein the latter informs his Hellenic counterpart that nine millennia have passed since the time of the mythical Atlantis, which, along with other flood narratives, such as those of the biblical Noah and the Mesopotamian Gilgamesh, is believed by scholars to echo the cataclysmic events surrounding the end of the last ice age, about 10,000 BCE.

• The Masoretic text of the Hebrew bible puts the date of creation around 4,000 BCE, which conveniently coincides with the dawn of urban civilization in the fertile crescent of the Levant, since it is about that time that the ancient cities of Ur, Uruk, and Nineveh were erected. The biblical character Abraham is said to have originated there (Genesis 11:28-31; 15:7).

We gather from the above that the sages of various nations have been capable of providing relatively decent chronological estimations involving an adequate amount of accuracy in dating certain pivotal moments in human history, though clothed -of course- in myth and legend, for at least the past twelve millennia, well before the introduction of writing around 3,500 BCE in Egypt and Mesopotamia.

2. When did humans start to keep track of years with unique identifiers for each year ?

Since it is doubtful that Ancient Egyptians counted their years since the end of the last ice age, and since biblical chronology most likely originates with the various court chroniclers serving at the palaces of Jewish kings, and immortalizing their ‘brave and glorious deeds’ with pen on parchment for all future generations to read and remember, the answers that you are probably looking for is the Seleucid era, which did indeed begin with Seleucus Nicator, as all other reckonings of regnal years did before him, but, unlike those, it did not end with his death, but rather continued undisturbed for whole centuries after his earthly demise. Though centuries older, neither the Greek Olympiads, nor the era of Nabonassar, let alone the ab urbe condita, can serve as good counter-candidates, since Greeks, Romans, and Babylonians commonly and formally used either regnal years or consular lists for dating various events.

Answer 3

The first recorded, truly written, dated calendar is the West Semitic Sumerian Calendar tradition starting from 3100 BCE. Month names are agricultural and pastoralist ones, they are a reflection of the society that used the calendar.

This Sumerian calendar tradition is found in clay tablets from Central and North Mesopotamia (Ebla, Mari, Gasur (later Nuzi), Abu Salabikh, Eshnunna, Drehem... sites). To learn more, look for books and articles by G. Pettinato.

Also, the first calendar tallies are a upper paleolithic invention. Even some middle paleolithic bone tallies have been 'suggested' to be calendars. This early use is debatable.

Furthermore, many early neolithic calendars have been found around the world. Interpretation is often difficult because there is no way to double-check the interpretation or reference the calendar to something else. Often, it is a just a cycle of symbols with a clear time-dimension, but nothing else can be said. The west Sumerian tradition is the first calendar tradition we can connect to early writing and there's plenty information about it to date and interpret it.