Argo Navis (or simply Argo) was a large constellation in the southern sky that has since been divided into three constellations. It represented the Argo, the ship used by Jason and the Argonauts in Greek mythology. Argo Navis is the only one of the 48 constellations listed by the 2nd century astronomer Ptolemy that is no longer officially recognized as a constellation. It was unwieldy due to its enormous size: were it still considered a single constellation, it would be the largest of all. In 1752, the French astronomer Nicolas Louis de Lacaille subdivided it into Carina (the keel, or the hull, of the ship), Puppis (the poop deck, or stern), and Vela (the sails).