In modern times there has been a long-running debate among historians, which is now 250 years old, about Ireland's Viking age and the Battle of Clontarf. The standard view, and the "popular" view, is that the battle ended a war between the Irish and Vikings by which Brian Boru broke Viking power in Ireland. However revisionist historians see it as an Irish civil war in which Brian Boru's Munster and its allies defeated Leinster and Dublin, and that there were Vikings fighting on both sides. In January 2018 researchers from the Universities of Coventry, Oxford and Sheffield, led by Coventry University theoretical physicist Professor Ralph Kenna, published a paper in the journal Royal Society Open Science, that used network science to mathematically analyse a medieval text, Cogadh Gáedhel re Gallaibh (The War of the Gaedhil with the Gaill, meaning invasions of Ireland by the Danes and other Norsemen), that listed over 1000 relationships between about 300 characters, and concluded that the standard and popular view of the war between the Irish and Germanic Norsemen was broadly correct, but that the picture was nevertheless more complex than "a fully 'clear-cut' Irish versus Viking conflict". However one of the paper's co-authors, PhD student Joseph Yose, added that “Our statistical analysis ... cannot decisively resolve the debate".