Construction of Piazzi was authorized by the Starfleet appropriation of stardate 4990. (TOS reference: Star Fleet Technical Manual) The stardate given would seem to suggest this ship was ordered sometime during the TOS era. It is not even known if this vessel was built, only that it was authorized. This ship class was named for scientists and astronomers, making it likey this ship was named after Giuseppi Piazzi, who, among other accomplishments, was the discoverer of Ceres.