Protagoras, the earliest self-proclaimed Sophist, was asked to write a constitution for the Athenian colony of Thurii, which was founded in 444 BC.

Thurii was a Greek city located in southern Italy, near the modern town of Corigliano Calabro in the province of Cosenza. It was founded by a group of Athenians and other Greeks as a new colony in the region and was intended to be a model city that would combine the best elements of Greek culture and society. Protagoras was asked to help design the city's political and social institutions, and he is credited with having contributed significantly to the development of Thurii's constitution.