Leonnorius was one of the leaders of the
Celts in their invasion of
Macedonia and the adjoining countries. When the main body under
Brennus marched southwards into Macedonia and
Greece (279 BC), Leonnorius and Lutarius led a detachment, twenty-thousand strong, into
Thrace, where they ravaged the country to the shores of the
Hellespont, compelled the city of
Byzantium to pay them
tribute, and made themselves masters of
Lysimachia. The rich Asiatic shores of the Hellespont afforded them a tempting prospect; and while Leonnorius returned to Byzantium, in order to compel the inhabitants of that city to give him the means of transporting his troops to
Asia, Lutarius contrived to capture a few vessels, with which he conveyed all the force remaining under his command across the Hellespont. While Leonnorius was still before Byzantium,
Nicomedes, king of
Bithynia, being in want of support in his war with his brother and
Antiochus, agreed to take him and his troops, as well as those of Lutarius, into his pay, and furnished them with the means of passing over into Asia (278 BC). They first assisted him against his rival brother,
Zipoites II, in Bithynia; after which they made plundering excursions through various parts of Asia; and ultimately established themselves in the province, called thenceforth from the name of its conquerors,
Galatia (region before known as part of
Phrygia). No farther mention is made of either of the leaders after they had crossed into Asia.