Theobald Dillon, 1st Viscount Dillon

Theobald Dillon, 1st Viscount Dillon (died 1624), was an Irish military commander and adventurer. He held extensive lands in eastern Connacht and north-western Leinster, some acquired by sharp practices. He was a loyal supporter of Elizabeth I of England in her Irish wars.

Theobald was born very approximately around 1530, probably at Ballynakill, the habitual home of his father and grandfather. He was the third son of Thomas Dillon and his wife Margery Dillon, also called Mary. His father was the eldest son of his grandfather James Dillon, nicknamed the Prior, because he took care of several monastic properties at the dissolution of the monasteries. His father's side of the family descended from Lord Dillon of Drumraney, County Westmeath. Theobald's mother was a daughter of Christopher Dillon of Kilmore. His father's family as his mother's family were branches of the same widespread Old English family that descends from Sir Henry Dillon who came to Ireland with Prince John in 1185.

Theobald appears below among his brothers as the third son:

1. Gerald, who married Cicely, daughter of a Dillon of High Baskin, County Westmeath;
2. Edmund, who lived in Ardnagrath Castle, County Westmeath;
3. Theobald (died 1624), the subject of this article;
4. Garret, a captain of an independent troop, ancestor of Garrett Dillon, Recorder of Dublin. and
5. James, from whom descend the Dillons of Ballynakill and some other Dillon cadet branches.

Theobald had three sisters:

1. Rose, who married Thomas Dillon, son and successor to Gerald of Drumrany;
2. Catherine, who married Edmund Fitz-Edmund Dillon of Kilcomane; and
3. Bridget, who married a Dalton of Moyvannane.

In 1559 Theobald commanded an independent force.

Theobald Dillon married Eleanor Tuite. So far the sources agree. However, she is either the widow or the daughter of William Tuite according to sources.

They had 19 children, eight sons and 11 daughters,

The sons were:

1. Christopher (died 28 February 1624), who was the eldest and married the eldest daughter of James Dillon, 1st Earl of Roscommon and became the father of the 2nd Viscount and the 4th Viscount;
2. Lucas, ancestor of the 7th and later viscounts;
3. William, styled of Tolchan;
4. Thomas, styled of Brackloon;
5. Edward, who became a Franciscan monk;
6. George, who became a Franciscan monk;
7. John, who became an officer in the army and died unmarried; and
8. James (c. 1600 – 1669), the 8th and youngest son, who became an army officer.

—and the daughters were:

1. Rose, who died young;
2. Margaret, who married Robert Dillon of Cannestown, son of Thomas Dillon, who was brother of Lucas Dillon, the judge;
3. Anne, who was the mother of Theobald Taaffe, 1st Earl of Carlingford;
4. Katherine, who married Sir Ulick Burke of Glinsk, 1st Baronet;
5. Mary, who married Gerald Pettyt of Mullingar in County Westmeath;
6. Elizabeth, to Thomas Fitzgerald of Newcastle in County Longford;
7. Jane, who married Hugh O'Conor of Castlereagh.
8. Eleanor (died 1629), who became a nun with the Poor Clares;
9. Cecily (c. 1603 – 1653), who became the first Abbess of the Poor Clares in Ireland;
10. Bridget, who died unmarried; and
11. Barbara, who died unmarried.

In 1582 in the context of the Composition of Connacht, a surrender and regrant action, Dillon was appointed collector-general of the composition money in Connacht and Thomond. During this period of the English reconquest in Connacht, Dillon was involved in some sharp practices with the local landholders. In particular he persuaded the various Costello freeholders of the Barony of Costello in eastern County Mayo, to save expense and ensure the smooth legal transfer, to allow him to surrender their lands for them in one land-title in the Surrender and regrant process and had it regranted in his own name, becoming the legal landowner in the process. He never returned this title to the lands to the native owners, which would lead to rapparee actions by Dudley Costello (or Costellogh) against the Dillons in the 1760s.

He fought under the Earl of Essex in the Nine Years' War (1593–1603) and was knighted by him on 24 July 1599. To put this into perspective it should be said that Theobald was already in his sixties and that Essex knighted a great many people and was mocked by saying "he never drew sword but to make knights".

On 19 July 1608, King James I gave him a patent confirming the possession of the manor and town of Kilfaughny in County Westmeath where he then lived and finally died.

On 16 March 1622, King James I created him Viscount Dillon of Costello-Gallen, cementing his legal title. He became the first of a long succession of viscounts Dillon. The territorial designation "Costello-Gallen" refers to the baronies of Gallen and Costello in County Mayo.

Lord Dillon, as he now was, held the title of Lord President of Connaught from c. 1621 on, which he shared with Charles Wilmot from 1616–1644.

Lord Dillon died on 15 March 1624 in Kilfaughny in County Westmeath. It is said that he died "at so advanced an age, that at one time he had the satisfaction of seeing above an hundred of his descendants in his house of Killenfaghny." Christopher, his eldest son, died on 28 February about two weeks before his father and therefore never succeeded his father. On the first Viscount's death, the title therefore passed to his grandson Lucas, Christopher's eldest son.