In 997 Brian Boru and Mael Sechnaill met at Clonfert and divided Ireland between them. This made Brian master of Dublin and Leinster. Late in 999 the Leinstermen and the Dubliners revolted against Brian; but he marched north and inflicted a crushing defeat on them at Glenn Máma, and took the king of Leinster prisoner. He followed this up with a winter war against Dublin; he plundered the city, burned the fortress, and eventually forced Sitric Silkenbeard, king of Dublin, into submission.58