| David de Barry | |
| Viscount Buttevant | |
| Tenure: | 1581–1617 |
| Predecessor: | James, 4th Viscount Buttevant |
| Successor: | David, 1st Earl of Barrymore |
| Issue: | David & others |
| Issue-Link: |
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| Father: | James, 4th Viscount Buttevant |
| Mother: | Ellen MacCarthy Reagh |
| Birth Date: | 1550 |
| Death Date: | 10 April 1617 |
David Fitz-James de Barry, 18th Baron Barry, 5th Viscount Buttevant (1550–1617), sided initially with fitz Maurice, the rebel, in the 1st Desmond rebellion but changed sides and fought against the rebels. He also fought for the crown in the Nine Years' War.
David, born 1550, was the second son of James de Barry and Ellen MacCarthy Reagh. His father was the 4th Viscount Buttevant. His father's family was Old English and owned much land in southern County Cork.
His mother was an illegitimate daughter of Cormac na Haoine MacCarthy Reagh, 10th Prince of Carbery. Her family were the MacCarthy Reagh, a Gaelic Irish dynasty that branched from the MacCarthy-Mor line with Donal Gott MacCarthy, a medieval King of Desmond, whose sixth son Donal Maol MacCarthy Reagh was the first independent ruler of Carbery.
David had four brothers and five sisters, which are (as far as known) listed in his father's article. David was the de facto 5th viscount as his elder brother Richard, the de jure 5th viscount, was deaf and dumb and was passed over in the succession.
Barry married firstly Ellen Roche, daughter of David Roche, 5th Viscount Roche of Fermoy by his wife Ellen Butler, daughter of James Butler, 10th Baron Dunboyne.
David and Ellen had a son:
—and six daughters:
At the outbreak of the First Desmond Rebellion in 1569, his father, the 4th Viscount Buttevant, supported the rebels. This rebellion ended when Fitz Maurice, the rebel leader, submitted to John Perrot, Lord President of Munster, at Kilmallock in 1573.
Barry succeeded his father in 1581.
Buttevant, as he was now, married secondly, Julia MacCarthy (also called Sheelagh), daughter of Cormac MacDermot MacCarthy, 16th Lord of Muskerry by his wife Mary Butler.
David and Julia had three sons and four daughters but nothing more seems to be known about them, not even their names.
In the subsequent confiscations of his estates, the friary in Buttevant, together with its glebe, passed into the hands of the poet, Edmund Spenser.
Buttevant was noted for his long and bitter feud with Sir Florence MacCarthy, the MacCarthy Mór, whose loyalty to the Crown was always suspect. Buttevant did great damage to his reputation by spreading rumours about MacCarthy's alleged acts of treason, in particular his links with Patrick O'Collun, whom Florence MacCarthy had once employed as a fencing master. In 1594 O'Collun was executed for conspiracy to kill Queen Elizabeth I. As a result, MacCarthy spent much of his later life in custody.
In 1601, during the Nine Years War Buttevant sided with the new President of Munster, Sir George Carew. In the wake of the Battle of Kinsale, he was granted large estates in Munster which had been forfeited by the MacCarthy Reagh.
Buttevant died at Barryscourt Castle 10 April 1617. His title and estate passed to his grandson, who became 1st Earl of Barrymore in 1628.