The Lapiths were a group of legendary people in Greek mythology, who were horsemen in the grasslands of Thessaly, in the valley of the Peneus and on the mountain Pelion, said to have invented the bridle's bit. They were an Aeolian tribe, like Achilles' Myrmidons, and descendants of Lapithes, a twin to Centaurus and son of the god Apollo and the Nymph Stilbe.
Lapithes was a valiant warrior, but Centaurus was a deformed being who later mated with mares producing the race of half-man, half-horse Centaurs. Lapith warriors and kings, included Ixion, Pirithous, Caeneus, and Coronus, and the seers Ampycus and his son Mopsus. In the Iliad the Lapiths sent forty manned ships to join the Greek fleet in the Trojan War, commanded by Polypoetes (son of Pirithous) and Leonteus (son of Coronus, son of Caeneus).
At the wedding of the Lapith King Pirithous and the horsewoman Hippodameia, the famous Centauromachy erupted when the invited centaur, Eurytion, unused to wine, upon meeting the bride leapt up and attempted to abduct her. In the battle that ensued, Theseus came to the Lapiths' aid. They cut off Eurytion's ears and nose and banished the centaurs from Thessaly.
In later retellings, the battle between Lapiths and Centaurs eventually took on aspects of the struggle between civilized and wild behavior and was used to demonstrate the necessity of tempering wine with water to avoid the consequences of excess. The Greek sculptors of the school of Pheidias depicted the battle of the Lapiths and Centaurs as a symbolic struggle between the civilized Greeks and "barbarians" on the Parthenon and on Zeus' temple at Olympia (Pausanias, v.10.8). The Battle of the Lapiths and Centaurs was also a familiar theme for classical Greek vase-painters.
Image: A centauromachy relief on an ancient Roman sarcophagus, c. 150 CE, at the Museo Archeologico Ostiense courtesy of Wikimedia Commons contributor, Sailko.