This deity is one of the most popular in Irish mythology. He was lord of the sea, beyond or under which the Land of Youth or Islands of the Dead were supposed to lie; he therefore was the guide of man to this country. He was master of tricks and illusions, and owned all kinds of magical possessions—the boat named Ocean-sweeper, which obeyed the thought of those who sailed in it and went without oar or sail, the steed Aonbarr, which could travel alike on sea or land, and the sword named The Answerer, which no armour could resist. White-crested waves were called the Horses of Mananan, and it was forbidden (_tabu_) for the solar hero, Cuchulain, to perceive them—this indicated the daily death of the sun at his setting in the western waves. Mananan wore a great cloak which was capable of taking on every kind of colour, like the widespread field of the sea as looked on from a height; and as the protector of the island of Erin it was said that when any hostile force invaded it they heard his thunderous tramp and the flapping of his mighty cloak as he marched angrily round and round their camp at night. The Isle of Man, seen dimly from the Irish coast, was supposed to be the throne of Mananan, and to take its name from this deity.
The greatest of the Danaan goddesses was Dana, “mother of the Irish gods,” as she is called in an early text. She was daughter of the Dagda, and, like him, associated with ideas of fertility and blessing. According to d’Arbois de Jubainville, she was identical with the goddess Brigit, who was so widely worshipped in Celtica. Brian, Iuchar, and Iucharba are said to have been her sons—these really represent but one person, in the usual Irish fashion of conceiving the divine power in triads. The name of Brian, who takes the lead in all the exploits of the brethren,(98) is a derivation from a more ancient form, Brenos, and under this form was the god to whom the Celts attributed their victories at the Allia and at Delphi, mistaken by Roman and Greek chroniclers for an earthly leader.
There was also an extraordinary goddess named the Morrigan,(99) who appears to embody all that is perverse and horrible among supernatural powers. She delighted in setting men at war, and fought among them herself, changing into many frightful shapes and often hovering above fighting armies in the aspect of a crow. She met Cuchulain once and proffered him her love in the guise of a human maid. He refused it, and she persecuted him thenceforward for the most of his life. Warring with him once in the middle of the stream, she turned herself into a water-serpent, and then into a mass of water-weeds, seeking to entangle and drown him. But he conquered and wounded her, and she afterwards became his friend. Before his last battle she passed through Emain Macha at night, and broke the pole of his chariot as a warning.