Roger O'Shaughnessy, The O'Shaughnessy (d. 1690), was a Captain in the Irish army of James II of England

James II of England

James II & VII was King of England and King of Ireland as James II and King of Scotland as James VII, from 6 February 1685. He was the last Catholic monarch to reign over the Kingdoms of England, Scotland, and Ireland...

. He was present 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...

, dying ten days after. In 1697 Roger's estates were granted to Sir Thomas Prendergast, 1st Baronet, and the O'Shaughnessy

O'Shaughnessy

Ó Seachnasaigh, O'Shaughnessy, collectively Uí Sheachnasaigh, clan name Cinél nAedha na hEchtghe, is a family surname of Irish origin.The name is found primarily in County Galway and County Limerick...

 family were never able to recover them.

He married Helen, daughter of Conor O'Brien, a son of Donogh O'Brien, 4th Earl of Thomond

Donogh O'Brien, 4th Earl of Thomond

Donogh O'Brien, 4th Earl of Thomond and Baron of Ibrickan was an Irish nobleman and soldier noted for his loyalty to the English Crown...

. Their sons were Dermot O'Shaughnessy and Major General William O'Shaughnessy, The 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...

.