Sir Roger O'Shaughnessey, Chief of the Name, died 1691.

Ó Seachnasaigh was married to Helena, daughter of Conor mac Donogh O'Brienn of Ballynue, by whom he had William and Helena. Sir Roger fought at the Battle of the Boyne

Battle of the Boyne

The Battle of the Boyne was fought in 1690 between two rival claimants of the English, Scottish and Irish thronesthe Catholic King James and the Protestant King William across the River Boyne near Drogheda on the east coast of Ireland...

 and though not wounded, died soon after at his castle in Gort

Gort

Gort is a town in south County Galway in the west of Ireland. An Gort is the official Irish name for the town, as defined by the Placenames Commission. In spoken Irish, however, the town is known by its traditional name Gort Inse Guaire. It lies just north of the border with County Clare on the...

. All his property was declared forfeit, and his son and heir, William O'Shaughnessy

William O'Shaughnessy

-Early life:William O'Shaughnessy was a member of the Uí Seachnasaigh of Cenél Áeda na hEchtge in south County Galway. His father was The Ó Seachnasaigh, Roger O'Shaughnessy, while his mother was Helen O'Brien, daughter of Conor mac Donogh O'Brien, a son of Donogh O'Brien, 4th Earl of Thomond...

, was forced into exile.