The Dorian invasion took place in Greece around 1000 BC . These Norse Dorian invaders would come to subjugate the primitive inhabitants of pre-Hellenic Greece, the Ionians, who were expelled from their fortified acropolis and then migrated to Asia and neighboring islands.
This occupation was not uniform throughout Greece. Some cities, such as Mycenae, were ruined while in others, as Athens, the Ionian element remained defensive. In the Peloponnese peninsula in contrast, Dorians effectively barricaded and Sparta became the great city of this region and the center of the Dorian race. Therefore Greece had to start again as if it was a primitive country. The Greeks themselves began to calculate their history beginning with the first Olympiad about the year 776 BC. For this reason, the study of Greek art and civilization starts in the centuries between the Dorian invasion and the formation of the Classical schools, which it’s called the archaic period .
This Dorian invasion was a key instrument in the decline of traditional art forms, and led to the formation of what is now called archaic schools, something like a “Greek Middle Ages”, which eventually led to the development of classical art whose peak was during the time of Pericles in Athens.
After the Dorian invasion certain elements that were characteristic of the Mycenaean civilization disappeared like for example the large walled acropolis. When the acropolis of Mycenae, Sparta, and Tiryns were abandoned the people from lower areas used the megaron of these cities for their religious ceremonies. Since the pre-Hellenic cult used symbols concerning the feminine principle, such as the ax and the pillar, the Dorian influence gave them human form which promoted the beginning of a primitive cult of Hera resulting in all kinds of plastic representations of this goddess. So it is not surprising that the most ancient Greek temples were those dedicated to Hera (eg, the temples of Hera in Argos and Olympia).
The structure of the Greek temple evolved from the pre-Hellenic megaron. By humanizing gods it was necessary to give them a human habitation and nothing more natural than they were granted as home the palace’s megaron, the most important place of collective life. Thus the cult should have started in the megaron of old palaces. When these palaces eventually fell into ruins, a small temple was built on the site of the old megaron. With the passing of time the devotees got tired of climbing to the old sanctuary where once stood the ancient acropolis of Mycenae and the cult moved to the plain in the neighboring city of Argos which was now the capital.
Then, the pre-Hellenic megaron greatly transformed. The floor plan continued to retain its cella* or naos and the antechamber or pronaos* of the megaron. A third element was added later, a chamber that was behind the cella and was known by the name of opisthodomos*. The megaron was thus enclosed inside a palace with three rooms, it had only a facade facing the courtyard, but since the temple was isolated it was decorated with another row of columns behind the building and a porch or colonnade surrounding the four facades.
This diagram shows the subsequent phases of the evolution of the Greek temple. A) The pre-Hellenic megaron. B) The temple of Ilisus had a portico with four columns surrounding the megaron on its front and rear facades. C) In the temple of Assos the cella lengthened and was completely surrounded by a colonnade on its four sides. D) The temple D of Selinunte, was completely surrounded by columns and divided into 1–pronaos, 2-naos or cella, and 3-opisthodomos. E) Finally, the Temple of Hera in Olympia, with the cella divided into three naves by two rows of columns and elevated from the ground level by several steps.
Sometimes the temples lacked this exterior colonnade and were called in Latin in antis because its facades only had the two columns of the pronaos like in the pre-Hellenic megaron. Sometimes the colonnade only decorated the two main facades with four columns and the temple was then called tetrastyle. When the colonnade also along the side walls, the front and back facades had six columns and then it was considered hexastyle, if it had eight columns then it was octastyle. In Western Greece there were only two octastyle temples: the Parthenon in Athens and a temple at Selinunte in Sicily. The hexastyle temples were the most abundant.
Generally, the in antis style which is the simplest, indicates antiquity. The age of a temple is also shown by the diameter of its columns: thicker and less separated in older buildings and slender and further apart in newer constructions. Another sign of age of a Greek temple is the length of the cella which appears longer and narrower in primitive buildings.
Sometimes the cella was divided into two aisles or naves by a central row of columns. When the cella was wider two rows of columns divided the interior of the temple in three naves, sometimes these lateral naves had two floors. A temple with three naves was the temple of Hera in Olympia, but the best preserved is that of Paestum in southern Italy supposedly dedicated to Poseidon or Neptune.
*Cella: (Latin for small chamber) or naos (Greek for temple), refers to the inner chamber of a temple in classical architecture.
*Opisthodomos: (Greek for “back room”) refers to either the rear room of an ancient Greek temple or to its inner shrine. Usually is used referring to the rear porch of a temple. On the Athenian Acropolis, the opisthodomos was a treasury, where the revenues and precious dedications of the temple were kept.
*Pronaos: The vestibule at the front of a classical temple, enclosed by a portico and projecting sidewalls.