The trireme was a large warship used by the Greeks and other peoples of the ancient world. About 120 feet by 20 feet, the Athenian trireme of the 4th century b.c. carried about 200 men, and moved at about 4 to 5 knots with the aid of a sail. The trireme, introduced in the 6th century B.C. as a replacement for the two-banked penteconter, fought chiefly by ramming. It is now generally believed that the oarsmen of the trireme did not sit on three levels, but rather on one deck of benches slanting forward, each of the three rowers on each bench operating a separate oar. In Hellenistic times, the trireme was superseded by the quinquireme.

Aurora, a phenomenon of the Arctic or Antarctic skies, known in the N. Hemisphere as the Aurora Borealis, and in the S. Hemisphere as the Aurora Australis. The term A. Polaris is sometimes used to include both. The Aurora usually occurs as an arc, or band, of white or colored light over the magnetic meridian, at a height of between 50 and 250 m., though in a sun-illumined atmosphere the light has been traced up to a height of 600 m. It appears doubtful whether it extends below the clouds.

Plutarch was a famous Greek essayist and biographer. Born Chaeronea, Greece, about 46 A.D. Died Chaeronea, about 120 A.D.