Jupiter (mythology) practice of swearing by Jove to witness an oath in law courts is the origin of the expression "by Jove!"—archaic, but still in use. The name of the god was also adopted as the name of the planet Jupiter; the adjective "jovial" originally described those born under the planet of Jupiter (reputed to be jolly, optimistic, and buoyant in temperament). Jove was the original namesake of Latin forms of the weekday now known in English as Thursday (originally called "Iovis Dies" in Latin). These became "jeudi" in French, "jueves" in Spanish, "joi" in Romanian, "giovedì" in Italian, "dijous" in Catalan,
Eclogues a new political mythology, Eclogue 4 reaches out to imagine a golden age ushered in by the birth of a boy heralded as "great increase of Jove" ("magnum Iovis incrementum"), which ties in with divine associations claimed in the propaganda of Octavian, the ambitious young heir to Julius Caesar. The poet makes this notional scion of Jove the occasion to predict his own up the scale in epos, rising from the humble range of the bucolic to the lofty range of the heroic, potentially rivaling Homer: he thus signals his own ambition to make Roman epic that will culminate in