On his second missionary journey Paul visited this city (Acts 17:15; comp. 1 Thess. 3:1), and delivered in the Areopagus his famous speech (17:22-31). The altar of which Paul there speaks as dedicated "to the [properly "an"] unknown God" (23) was probably one of several which bore the same inscription. It is supposed that they originated in the practice of letting loose a flock of sheep and goats in the streets of Athens on the occasion of a plague, and of offering them up in sacrifice, at the spot where they lay down, "to the god concerned."