The Celtic heroic saga in the British islands may be divided into the two principal groups of Gaelic (Irish) and Brython (Welsh), the first, excluding the purely mythological, into the Ultonian (connected with Ulster) and the Ossianic. The Ultonianis grouped round the names of King Conchobar and the hero Cuchulainn, "the Irish Achilles," the defender of Ulster against all Ireland, regarded by some as a solar hero. The second cycle contains the epics of Finn (Fionn, Fingal) mac Cumhail, and his son Oisin (Ossian), the bard and warrior, chiefly known from the supposed Ossianic poems of Macpherson. (See CELT, sec. _Celtic Literature_.) Of Brython origin is the cycle of King Arthur (Artus), the adopted national hero of the mixed nationalities of whom the "English" people was composed. Here he appears as a chiefly mythical personality, who slays monsters, such as the giant of St Michel, the boar Troit, the demon cat, and goes down to the underworld. The original Welsh legend was spread by British refugees in Brittany, and was thus celebrated by both English and French Celts. From a literary point of view, however, it is chiefly French and forms "the matter of Brittany." Arthur, the leader (_comes Britanniae, dux bellorum_) of the Siluri or Dumnonii against the Saxons, flourished at the beginning of the 6th century. He is first spoken of in Nennius's _History of the Britons_ (9th century), and at greater length in Geoffrey of Monmouth's _History of the Kings of Britain_ (12th century), at the end of which the French Breton cycle attained its fullest development in the poems of Chretien de Troyes and others.