She was the daughter of Sir Nicholas Bagenal, an English-born adventurer who had fled to Ireland following accusations of murder in his native Staffordshire.
He received the patronage of the Gaelic lord Conn O'Neill, 1st Earl of Tyrone and established himself in Newry.
[1] Amongst her siblings were Sir Henry Bagenal, the Marshal of Ireland, and Mabel Bagenal, the wife of Hugh O'Neill, Earl of Tyrone whose forces killed Sir Henry at the 1598 Battle of the Yellow Ford during Tyrone's Rebellion.
Such dynastic alliances were typical of the newly established Protestant landed families of Ireland.
He was a man of great strength of character, but as a judge became so notorious for corruption that he was finally removed from office in 1633.