As the mythological references made in a few poems may partially obscure the meaning for those unacquainted with Celtic tradition, I have appended here a brief commentary on the names mentioned.
Angus, the Celtic Eros. In the bardic stories he is described as a tall, golden-haired youth playing on a harp and surrounded by singing birds. The kisses of these birds created love and also brought death.
Balor, the prince of the dark powers. His eye turned every living thing it rested on into stone. He was killed at the battle of Moytura by Lugh the Sun-god.
Dana, the Hibernian mother of the gods who were named from her Tuatha De Danaan, or the Tribes of the goddess Dana. They are also sometimes called the Sidhe.
Etain, a Celtic goddess who is the subject of a famous story, "The Wooing of Etain." She left the heaven world and became the wife of an ancient Irish king.
Lir, the Oceanus of Celtic mythology. Probably the Great Deep or original divinity from whom all sprang. His son Mananan MacLir was the most spiritual divinity known to the ancient Gael. Lir is more familiar as the father of the children who were changed into swans by magic, and who lived for long ages on the waters around the Irish coast. The story of the fate of the children of Lir was probably in its earliest form a mythological account of the descent of the spirit from the Heaven-world to the Earth and its final redemption.
Lugh, the great god of light who led the De Danaans at the battle of Moytura, and who slew Balor of the Evil Eye by a cast from his sling. He is a Celtic Hermes or Apollo.
Fomor, the dark powers who were opposed to the hosts of light, the Tuatha De Danaan. They enslaved the latter for a time until the De Danaans rose, led by Lugh the Sun-god, and defeated the Fomors in the battle of Moytura.
Silver Hand. Nuada, one of the Danaan divinities, is called Nuada of the Silver Hand.
Hound of Ulla. Cuculain, the great champion of the Red Branch cycle of tales.