Lucas Dillon, 6th Viscount Dillon

Lucas was born in Ireland as the eldest son of Theobald Dillon and his wife Sarah Bourke.^[1] His father was the third son of Christopher Dillon, who was the eldest son and heir apparent of Theobald Dillon, 1st Viscount Dillon.^[2][3] The Dillons are an Old English family, established in 1185 when Sir Henry Dillon came to Ireland with Prince John.^[4] Lucas's mother was an illegitimate daughter of David Bourke, who was a younger son of Theobald Bourke, 1st Viscount Mayo. Her family, the Mayo Bourkes, were Gaelicised Old English.^[1]

He heads the list of siblings below as the eldest:

1. Lucas (died 1682)
2. James, who was a captain in the army^[5]

His sisters were:

1. Honora, who married firstly Robert Dillon of Lisnagragh and secondly James Dillon of Rathmane^[6]
2. Bridget, who married a Dillon of County Mayo^[7]

Lucas's uncle Thomas Dillon, 4th Viscount Dillon, died in 1673^[9][10] and was succeeded by his only surviving son, also called Thomas Dillon, Lucas's cousin. Thomas Dillon, the 5th Viscount died without surviving children a year later.^[11] Lucas succeeded him as the 6th Viscount Dillon in 1674. On 28 February 1675 he granted a yearly pension of £600 (about £110,000 in 2023^[12]) to Elizabeth, the widow of the 5th Viscount.^[13]

Lord Dillon, as he was now, married firstly Ursula, daughter of William Dongan, 1st Earl of Limerick,^[14] by Maria Euphemia, daughter of Sir Richard Chambers, Baronet. Ursula died childless in 1680.^[15] In 1682 he married secondly Lady Anne Nugent, daughter of Richard Nugent, 2nd Earl of Westmeath.^[16]