Over a century ago the Rev. Charles O'Conor published in his corpus of Irish historical writers a collection of annals, the authorship of which he ascribed to a certain Tigernach ua Braein, abbot of Clonmacnois, who died in the year 1088. This ascription O'Conor apparently adopted from Sir James Ware, and it is not unlikely that Ware took it from the learned Irish scholar Dubhaltach mac Firbhisigh who was in Ware's employment. Mac Firbhisigh probably had good reason for describing Tigernach as abbot of Roscommon as well as of Clonmacnois. There had been for centuries a close connexion between the two monasteries, and both were favoured with the protection of the kings of Connacht. For the rest, government of more than one monastic community by the same individual was quite common. Ua Braein was one of the family names of the sept of Clann Murchada, which is mentioned several times in the Irish annals and elsewhere.