In 980, Máel Sechnaill Mór defeated the Dublin Vikings and forced them into submission. Over the following thirty years, Brian Boru subdued the Viking territories and made himself High King of Ireland. The Dublin Vikings, together with Leinster, twice rebelled against him, but they were defeated in the battles of Glenmama (999) and Clontarf (1014). After the battle of Clontarf, the Dublin Vikings could no longer "single-handedly threaten the power of the most powerful kings of Ireland". Brian's rise to power and conflict with the Vikings is chronicled in "Cogad Gáedel re Gallaib" ("The War of the Irish with the Foreigners").