 Notable regional kingdoms and lordships of Early Medieval Munster were Iarmuman (West Munster), Osraige (Ossory), Uí Liatháin, Uí Fidgenti, Éile, Múscraige, Ciarraige Luachra, Corcu Duibne, Corcu Baiscinn, and Déisi Muman.By the 9th century, the Gaels had been joined by Norse Vikings who founded towns such as Cork, Waterford and Limerick, for the most part incorporated into a maritime empire by the Dynasty of Ivar, who periodically would threaten Munster with conquest in the next century.Around this period Ossory broke away from Munster.