After the death of Fergal Mág Tighearnán the Third in 1588, Brian Mág Tighearnán became ceann fine ('head of the lineage') and resided in the castle of Croghan UaCúbhrán ('Croaghan of the Cups', now in the townland of Coolnashinny, beside the modern town of Killeshandra.
They marched that night to Teallach-Eachdhach, west of Bel-atha-Chonaill; and from thence they returned home, after the victory of expedition on that occasion.On 9 June 1602 Queen Elizabeth I of England granted a pardon (fiant No.
4d., to Bryan McKearnan, gentleman, comprising the modern-day townlands of Clontygrigny, Cornacrum, Cornahaia, Derrinlester, Dring, Drumlarah, Ardlougher and Kiltynaskellan.
In a visitation by George Carew, 1st Earl of Totnes in autumn 1611, it was recorded, McKyernan removed to his proportion and is about building a house.
[6] On 14 March 1630 an Inquisition of King Charles I of England held in Cavan Town stated that Brian McKiernan died on 4 September 1622, and his lands comprising seven poles and three pottles in Clonkeen, Clontygrigny, Cornacrum, Derrinlester, Dring, Killygorman, Kiltynaskellan, and Mullaghdoo, Cavan went to his nearest relatives.