The gatherings of which group drive such innovations as the development of major-minor tonality, the development of equal-tempered tuning, and the recreation of the musical styles of ancient greece?

The gatherings of the philosophical group called peripatetics led in music subject by Aristoxenus, helped drive such innovations as the development of major-minor tonality, the development of equal-tempered tuning, and the recreation of the musical styles of Ancient Greece.

Explanation:

Aristoxenus was born in 375 bc in Tarentum, a Greek city in southern Italy and belonged to the group of philosophers called Peripatetics.

He is considered currently the most relevant  music´s  theorist in the classical world due to his empirical approach given in his work called Elementa harmonica where he vastly wrote  about equal-tempered tuning and major-minor tonality and how these are related to the human soul as harmony and how they needed to be evaluated as a sole system by ear voiding cosmology and ethics. He seemed to follow Pythagorean theory

Aristoxenus  flourished in the time of Alexander the Great  who reigned in 336-323 and he was Aristotle´s pupil too.

Nowadays he became a key source for the study of ancient Greek music styles . It is said that he gave birth to musicology.