As a semi-reconstructionist polytheistic pagan, I draw upon a variety of sources–historical, literary, archaeological–to inform my religious practice. Such sources do not define my practice but they do provide a base on which to build it.
Reconstructionism is a broad term, used by some who follow “interrupted” religions (most often interrupted by the arrival of monotheism in a region), describing a religious practice with strong roots in the past. Some folks attempt to recreate the original historical practices (and, sometimes, to adopt the ancient world view and cosmology) as closely as possible; some try to build a faith that reflects what might have been, if that faith had continued into modern times without interruption; others focus on a restoration of the faith within the existing modern world.
When I say that I consider myself a semi-reconstructionist, what I mean is that I feel that the ancient practices are deeply important and provide a solid template, but don’t suffice on their own, and where I go from there is a matter of choice. I also recognize that there was a wide range of practices in ancient times, something not only worthy of study on its own but also an indication of just how much social and cultural factors can affect the practice of a religion.
In this series of posts, I hope to discuss some of the information provided by historical sources and how it can be relevant in a modern religious practice. I hope also to provide a very brief overview of some useful information and terminology. I apologize for the inevitable dryness of some of this material. 
The ancient Greek religion existed over hundreds of years, and did not stay the same over all that time. While there are a number of overarching consistencies, the particulars of practice (and belief) are known to have shifted considerably over the years.
From our modern point of view, Greek history is usually broadly divided into three eras: the Archaic, the Classical, and the Hellenistic, together roughly comprising the period from 800-60 BCE. Earlier information is spottier, the Greek Dark Ages particularly so. These divisions are not precise, and can vary depending on which scholar you ask; the dates are based on different guidelines–for example, some scholars focus on military and other historical events, others on archaeological evidence such as styles of pottery. In either case there is rarely a sharp cut-off date when one era ends and the next begins, but the eras are still a useful way to look at the development of religion within the ancient Greek world.
Dark Ages
The Greek Dark Ages are usually said to have taken place from the end of the Mycenaean civilization (roughly 1200 BCE) until the emergence of the Greek city-state or polis, when the Archaic Era began. With little in the historical record from this period of time (unsurprising given the loss of literacy), much of what we know about the culture or the religion during this time is archaeological evidence.
During the Dark Ages, some of the significant knowledge of earlier eras was lost. An understanding of Linear B*, the written language of the Mycenaean age, was not regained until 1952 CE (Linear A, the language of the Minoan age, has not yet been deciphered). Communities became more isolated from one another and less densely populated overall.
Archaic Era
The Archaic era (sometimes known as the Homeric Era because Homer’s works date to this period) is usually said to have taken place from the late 9th to early 8th century BCE (a common starting date is 776 BCE, the date of the first Olympic games) until the beginning of the Classical Era.
During the Archaic period there was a return of literacy with the development of the Greek alphabet still in use today, and a strengthening of the overall economy. The concept of the Greek city-state or polis began to develop and grow. There were many, many poleis; over a thousand are know to have existed over time, although there may well have been some overlap, and each had its own identity and unique features. Athens began its growth to greatness at this time. Artistic accomplishment grew and changed as well, with the development of lyric poetry in addition to epic (this was the era of Sappho).
Classical Era
The Classical era is generally said to begin in the late 5th to early 4th century BCE. A commonly suggested starting date is 479 BCE, with the defeat of the Persian invasion of Xerxes; another is 510 BCE, with Cleisthenes’ reforms and a solid base for democracy. The era is almost always said to end in 323 BCE with the death of Alexander the Great.
Most people probably think of the Classical era when they hear the term “ancient Greece”; much of the art, architecture and literature we are familiar with dates from this era. It was as well the age of the philosopher, the age of Socrates and Plato. The study of mathematics and the sciences flourished, as did literature–history, theater, poetry and prose. The Classical era has been considered by many to be a Hellenic “Golden Age,” greater than that which preceded it and that which followed.
Hellenistic Era
The Hellenistic Era begins with the end of the Classical Era in 323 BCE with the death of Alexander the Great, and ends roughly in 31 BCE with the coming to power of the Roman Empire and the death of Cleopatra in 30 BCE.
Expansion is a mark of the Hellenistic era; after his death, Alexander’s empire grew to include parts of Africa (Egypt in particular) and Asia, as well as greater portions of Europe. The Hellenic/Greek culture expanded its influence into these regions as well. This exchange was not a one-way affair–as the Greek culture influenced other regions, it was influenced by them as well, making Greece a bit more cosmopolitan as the surrounding areas were made a bit more Greek. New gods were worshipped, new religious practices adopted (a trend less marked in the mainland of Greece than on the periphery, yet still apparent); variants on the Egyptian gods Isis and Serapis were particularly wide-spread, as were the cults of Eastern gods like Mithras and Cybele.
The Parameter of Time
Some folks think of “Greek religion” as a singular entity; the truth is, this was not the case during any era of Greek history that we know of. There were always regional differences, differences that may have been more marked depending on time, region, and the amount of contact that region had with other regions. For almost any generalized fact there are a number of smaller, specific, contrary facts. For almost any rule there are exceptions.
That said, some folks feel a particular affinity for a particular period of time. There are folks who prefer to focus on what is known from the earlier historical period, the Archaic; they draw primarily on resources dating from that era, they perhaps prefer to use god-images derived from Archaic art on their altars. Others, who take a more syncretic view of deity and religion, might draw on the more religiously expansive Hellenistic era for inspiration.
*While a majority of Linear B documents were primarily administrative in nature, a number of familiar deity names appear within them, including Poseidon, Dionysos, Zeus and Hera. This does not provide evidence of specific religious practice but does indicate some level of religious continuity dating back to perhaps 1600 BCE.
