e heroic cycle of Ulster, which had its centre
in the deeds of the Ulster king, Conchobar Mac Nessa, and his
nephew and chief warrior, Cuchulainn Mac Sualtaim. Tradition places
their date at the beginning of the Christian era.

The events leading up to this tale, the most famous of Irish
mythical stories, may be shortly summarised here from the Book of
Leinster introduction to the _Tain_, and from the other tales
belonging to the Ulster cycle.

It is elsewhere narrated that the Dun Bull of Cualnge, for whose
sake Ailill and Medb [Note: Pronounce _Maive_.], the king and queen
of Connaught, undertook this expedition, was one of two bulls in
whom two rival swineherds, belonging to the supernatural race known
as the people of the _Sid_, or fairy-mounds, were re-incarnated,
after passing through various other forms. The other bull,
Findbennach, the White-horned, was in the herd of Medb at Cruachan
Ai, the Connaught capital, but left it to join Ailill's herd. This
caused Ailill's possessions to exceed Medb's, and to equalise
matters she determined to secure the great Dun Bull, who alone
equalled the White-horned. An embassy to the owner of the Dun Bull
failed, and Ailill and Medb therefore began preparations for an
invasion of Ulster, in which province (then ruled by Conchobar Mac
Nessa) Cualnge was situated. A number of smaller _Tana_, or
cattle-raids, prefatory to the great _Tain Bo Cuailnge_, relate
some of their efforts to procure allies and provisions.

Medb chose for the expedition the time when Conchobar and all the
warriors of Ulster, except Cuchulainn and Sualtaim, were at their
capital, Emain Macha, in a sickness which fell on them periodically,
making them powerless for action; another story relates the cause
of this sickness, the effect of a curse laid on them by a fairy
woman. Ulster was therefore defended only by the seventeen-year-old
Cuchulainn, for Sualtaim's appearance is only spasmodic.
Cuchulainn (Culann's Hound) was the son of Dechtire, the king's
sister, his father being, in different accounts, either Sualtaim,
an Ulster warrior; Lug Mac Ethlend, one of the divine heroes
from the _Sid_, or fairy-mound; or Conchobar himself. The
two former both appear as Cuchulainn's father in the present
narrative. Cuchulainn is accompanied, throughout the adventures
here told, by his charioteer, Loeg Mac Riangabra.

In Medb's force were several Ulster heroes, including Cormac
Condlongas, son of Conchobar, Conall C