Lady Desmond was the daughter of Sir John FitzGerald, second Lord of Decies in Waterford, and Ellen Fitzgibbon. She was probably born at
Dromana, in County Waterford. In 1529, she married, becoming the second wife of
Thomas FitzGerald, 11th Earl of Desmond (1454–1534), "her
cousin german once removed", and a man some fifty years her senior. (His previous wife had been Síle Ní Chormaic, daughter of Cormac Láidir Mac Cárthaigh, builder of
Blarney Castle.) The couple had a single daughter, also named Katherine, and she remained a widow following the death of her husband in 1534. In later life, Lady Desmond was party to a property dispute typical of late-Tudor Ireland (1485–1603). Her husband had granted her a life tenancy in Inchiquin Castle, about 5 miles southwest of the town of
Youghal, in
Munster. Upon the Countess Desmond's death the castle was to revert to the line of the Earls of Desmond. In 1575, she passed title to the castle and lands in trust, by deed, to the incumbent earl,
Gerald FitzGerald, who then passed it in trust to his dependants. (The Earl, who was in rebellion against the Crown, wished to avoid confiscation of his lands by placing them in the legal guardianship of others.) The estate of Inchiquin was described at the time as "the castle and towne of Inchiquaine, with arable land called the six free plowelands in Inchiquaine, together with mores, meadowes, pastures, groves, woodds, mill places, with their watercourses, rivers, streams, with their weares and fisheryes". Following the earl's
attainder in 1582, whereby his estate fell to the Crown after the
Desmond Rebellions, Inchiquin Castle and its lands were granted to
New England colonist Sir Walter Raleigh who then leased out some of the land while preserving the life interest of the Countess in the castle. She survived far beyond Raleigh's expectations. Sir
Richard Boyle, who purchased Raleigh's colonial possessions in Ireland, including the castle, was later said to have brought proceedings to evict the old lady, though the evidence is unreliable. A legend claims that, to protect her interests in the castle, the impoverished "old Countess" set out from
Cork in 1604. After sailing to Bristol, she walked the road to London with her invalid 90-year-old daughter, whom she pulled along in a cart. It was later argued that this story arose from a confusion with another dowager countess of Desmond, Elenor, who travelled to London to petition
Elizabeth I. This countess was the widow of
James FitzGerald, 14th Earl of Desmond who had died in 1558 and was the nephew of Katherine's husband. == Death ==