The Skeptics filled this function...

The Skeptics filled this function: the thought common to this school is that we cannot know the nature of things: Pyrrho [365-270 BCE] may be called the founder but wrote nothing: his views were set down by Timon of Phlius [320-230 BCE].

After Timon, the Skeptical school was absorbed by the Platonic Academy and did not emerge as an independent school until the Academy called the Middle Academy during the Skeptical period purged itself of Skepticism under Philo of Larina and Anticus: Skepticism again became an independent movement at the beginning of the Christian era and was later represented by Sextus Empircus. Eclecticism was encouraged by the growing intercourse between Greek scholars and the Romans.

The Romans had no genius for philosophy; it was only after Rome conquered Macedonian 168 BCE and Greece became a Roman Province [146 BCE] that interest arose in philosophical speculation.

The Romans produced no independent system: they selected and modified according to their practical needs: "They sought and found in Philosophy, nothing but a rule of conduct and a means of government." Subsequently, Eclecticism made its way into nearly all the schools, into the Academy [Plate], the Lyceum [Aristotle] and the Stoa; the Epicureans alone remained true to their creed.

2.4.3 Stoicism continued Zeno [336-264 BCE] b Citium, Cyprus, came to Athens in 314, and in 294 opened his school in the Stoa Poikile [painted corridor or porch, from which "Stoicism"] and was founder of the school.

Zeno was esteemed for his upright character, the simplicity of his life, his affability and moral earnestnessHe was followed by his pupil Cleanthes [264-232 BCE] who lacked the qualities needed to defend the school against the Skeptics and the EpicureansNext came Chrysippus of Soli, Cilicia [232-204 BCE], a man of great ability who clearly defined the teachings of the school, gave unity to the system, and defended it against the Skeptics.

His pupils included Zeno of Tarsis, Diogenes of Babylon, Antipater of TarsusStoicism as developed by Chrysippus found favor in Rome during the Republic: Panaetius [180-110 BCE] being one of the first Roman adherents of note.

During the Empire it divided into two schools: one popular, represented by Musonius Rufus [first century CE], Seneca [3-65 CE], Epictitus [first century CE] and Emperor Marcus Aurelius [121-180]: the other scientific, whose sole aim was to preserve intact and interpret the old doctrine.