The Subject in Art, (No. 1.)

Jason
Hero of Greek legend who lead the Argonauts on the quest for the Golden Fleece. Husband of Medea.

Centaurs and Lapithae
According to Greek legend, the half-man, half-horse centaurs of Thessaly disgraced themselves at the marriage feast of Hippodamia by being rude to the ladies present. The Lapithae, a people of Thessaly, defended the women by driving the centaurs out of country. Their battle is depicted on innumerable ancient Greek vases as well as on the Parthenon, the Theseum at Athens, and the Temple of Apollo at Bassae.

Irus
In Greek legend, Irus was a poor beggar who ran errands for Penelope's suitors when her husband Ulysses was presumed dead. When Ulysses returned home in beggar's garb, Irus challenged him, and was felled by a single blow from Ulysses. "As poor as Irus" is a proverb.

two triangles in Euclid
Euclid was a Greek mathematician who taught at Alexandria around 300 B.C. He developed Euclidian geometry in his Elements.

Jacques, Ferdinand, or Cordelia
Characters in Shakespeare's plays As You Like It, The Tempest, and King Lear, respectively.