In 1603 after the end of the
Desmond Rebellions the Chief of the time was attainted as a result of his participation in the rebellion but was later able to regain his title and lands in 1609. The heart of rebellion still remained though, for in February 1642 Tadhg O'Donoghue and his three sons, Geoffrey, Tadhg and Daniel participated in the siege of Tralee Castle. In 1643,
Geoffrey the Poet became Chief. He was noted for his lavish banquets at the top of Killaha Castle, but that all changed after the
Cromwellian conquest of Ireland. He lamented: :::Time was when I saw the Gaedhil in silks and in jewels, :::Capable, propertied, earnest, perceptive, just, :::Merry, sagacious, noble, lordly, intrepid, :::Poetical, truthful, wine-loving, feasting – once. They became notorious as the 'Dangerous O'Donoghues' who constantly harassed the English colony brought into the Killarney region by the undertaker Browne family, known as the
Earl of Kenmare. In the late 18th century, the Glen was a haven during the
Rightboy Movement which originated in Munster. The
Down Survey estimated the territory of The Glens to be five quarters, each of four
ploughlands (a ploughland being roughly 120 acres), although this does not include the "unusable" lands controlled by the sept. It indicates that The Glens paid MacCarthy Mór forty shillings annually. 'No explanation is given as to why this clan was so slightly assessed.' Throughout the centuries, the Glens family managed to retain their title and territory, and eventually built Killaha House near their ruined castle. The Chiefs were consistently devoted to Irish independence and one of the few Gaelic magnates who did not conform to the established Church. They remained in their territory throughout the years of English oppression, never faltering from their faith or deserting their clann. In the middle of the 19th century
Daniel Ó Donoghue, MP from Tralee, married Marie Sophie Ennis, the only daughter and heiress of
Sir John Ennis. Upon the death of her father, the family moved to her estate at Ballynahown Court near Athlone. Killaha House became a Presbytery in 1887 and is currently in private hands. The ruined castle is now a national monument owned by the
Office of Public Works. ==21st century==