Who are Ancient Philosophers?

The Ancient era of philosophy can be further sub-divided into these major historical periods:

Pre-Socratic (7th – 5th Century B.C.)
Socratic (5th – 4th Century B.C.)
Hellenistic (3rd Century B.C. – 3th Century A.D.)
Roman (1st Century B.C. – 5th Century A.D.)

The dates are just rough guides, and the classifications rather arbitrary (for example, the Hellenistic period is usually considered to apply to the spread of Greek culture to non-Greek lands, and the Roman period to end with the fall of Rome in the 5th Century, but there is obviously also a certain amount of overlap).