Hellenism
Hellenism is torn between hule and morphe.
Morphe is "form", the product of the masculine imagination personified by the gods of Olympus, above all by "bright Apollo", patron of all human development.
Hule represents the unrestrained feminine sentience celebrated in revering Dionysus god of revels.
Hule originally denoted wood, but Aristotle of Stagira gave it a broader sense, usually translated "matter" but incorporating the wild and amorphous in general.
Since Nietzsche, morphe and hule have been called "Apollonian" and "Dionysian".
Hellenism dominated Eastern Europe from 300 BC to 1450 CE and Western Europe to maybe 1100 CE.
In Europe, the period of Hellenism's dominance has often been called Classical (big C) because its products have been widely regarded as a standard to be imitated but not surpassed.
Chronology
Pre-Classical (before 480 BC)
Thinkers speculated about the constitution of the world. None of these authors is extant. Their thoughts are gathered from quotations and comments in Classical authors.
Thales (-600) is regarded as the first "philosopher".
Pythagoras (-550) held that arithmetic was the ultimate truth about the world.
Classical (480 BC to 323 BC)
Parmenides (-450), orientated to Form, held that ultimate reality was one and static.
Heraclitus (-450), orientated to Matter, that is was many and dynamic.
Aeschylus' Oresteia trilogy, the oldest extant European drama on that scale, represents the tension between the two elementary attitudes. Agamemnon and Clytemnestra are father and mother of Orestes and Electra. In the backstory, A kills E for reasons of state. In Part 1, C kills A in revenge. In Part 2, O kills C in retribution. In Part 3 O stands trial, accused by the (feminine) Furies representing hule and defended by Apollo himself. The jury being tied, Athena acquits; to seem to condone C would reinvigorate the old matriarchy. The Furies are persuaded to accept a subordinate role in the new order.
Socrates turned attention from nature to human values. He invented dialectic, and coined "wisdom lover" ("philosopher"), emphasising method rather than results.
Plato held that an abstract noun is the name of an essence that subsists independent of instances.
Aristotle held that abstractions only subsist in their instances.
Post-Classical (323 BC to 600 CE)
The Romans learned ontology from the Greeks they conquered, but produced nothing pivotal.
Epicurus founded Epicureanism.
Zeno of Kition founded Stoicism.
Plotinus' Neoplatonism's seemingly wild speculations are actually reflections on the nature of thought and motivation.
Augustine of Hippo adopted Christianity and gave his Neoplatonism a Christian veneer.
Dark Ages (Early Middle Ages) (600 to 1100)
Barbarian invasion combined with ascetic tendencies led the best minds to the cloister where they produced nothing pivotal.
Anselm's Ontological Argument is the first attempt at synthetic a priori knowledge. It "proves" the existence of God from the definition of God.