James Eustace, the eldest son of the 2nd Viscount, was born in 1530 and had as his tutor an influential priest, Sir Norman Eustace. He became a fervent Catholic and regarded Queen Elizabeth as an illegitimate heretic. In 1576, before the death of his father, he lodged complaints against the persecution of Catholics and illegal taxation of the Lord Deputy, Sir Henry Sydney. He and other leading Catholics were imprisoned in 1577, and lie was released only just in time to assume his title the next year. He married Mary, daughter and co-heiress of Sir John Travers of Monkstown Castle, but they had no children. She died in 1610, having married secondly, in 1587, Sir Gerald Aylmer, Bart., of Donadea, a Catholic loyalist, repeatedly imprisoned, but finally released and knighted, by Elizabeth and created a baronet by James I.

In 1579, Gerald FitzGerald, 14th Earl of Desmond, took up arms in Munster against the Queen, who appointed Thomas Butler, the 10th “Black” Earl of Ormonde to deal with the rebellion. This he eventually did, but with ruthless and terrible severity. In the summer of 1580, Baltinglass, apparently prompted almost entirely by religious motives, collected rebel forces in Wicklow, with a view to assisting Desmond. These included many influential Catholics, some of them his own relatives, and large numbers of Irish tribesmen. News of this soon reached the ears of Ormonde, his brother-in-law, (Edmund Butler, brother of Ormonde, had married Eleanor, Baltinglass's sister) who must have sent him a severe warning, for we have Baltinglass's defiant reply, later produced in evidence against him. At first the revolt was remarkably successful, and a severe defeat was inflicted upon the troops of the Lord Deputy at the Pass of Glenmalure in the Wicklow Mountains on the Baltinglass lands. But Baltinglass never coordinated his efforts with those of Desmond, and in any case had started too late. There was desultory fighting for nearly a year, but with no large engagement, and the Baltinglass troops over-ran a large area doing great damage, but were then hopelessly overpowered. (The Annals of the Four Masters states that, “the entire extent of country from the Slaney to the Shannon and from the Boyne to the meeting of the Three Waters became one scene of strife and dissension.”) A force of Spaniards and Italians had landed at Smerwick, Co. Kerry, in order to assist the Catholic cause, but when they had completed the long march of 150 miles to Naas were taken prisoner and massacred. The scene of this massacre, on the southern edge of the town, is still called Spaniards' Cross or Foad Spaniagh. Baltinglass and his followers were outlawed and forty-five of them were hanged in Dublin. He himself escaped to Munster, where Desmond was still in revolt, and thence to Spain. He was well received, and only just failed to persuade King Philip to provide sufficient troops and ships to invade Ireland. He died there childless in 1585. The fates of his five brothers were as follows:

·    Edmund Eustace had married Frances, daughter of Robert Pipho, and secondly Joan, daughter of Richard Walsh of Carrickmines, who afterwards married Dermot Kavanagh of Knockangary. In 1583 he escaped to Scotland and thence to Spain, where he was created “4th Viscount” by the Pope. He served against England in the Armada in 1588, and died childless in Portugal in1597.

·   Thomas was executed in 1582.

·   William was certainly believed to have been slain in battle in 1581, for it was officially reported to Sir Francis Walsingham, Secretary of State in London, "Head of William Eustace, another of the Baltinglass brethren, taken this morning." It is, possible however that this report was untrue and that he was the ancestor of the Eustaces of Robertstown whose distinguished line will be dealt with later.

·   Walter was captured in 1583 and executed.

·   Richard was in Paris at the time of the rebellion, engaged in arranging for the dispatch of ammunition and supplies to assist his brothers. He became a priest in Rome.

Of their sisters, Joan married Sir Barnaby Fitzpatrick of Upper Ossory and Eleanor married Sir Edmund Butler, the second son of the ninth Earl of Ormonde.Among the other Eustaces who took part in the Baltinglass Rebellion were Maurice Eustace of Castlemartin and Thomas Eustace of Kerdiffstown who were both executed, and John Eustace of Newland and Oliver Eustace of Blackhall, who were eventually pardoned, as was Maurice FitzGerald of Osberstown, who was the husband of Baltinglass's aunt Janet.

In 1585, the Statute of Baltinglass was passed by Parliament, but against considerable opposition. Under this Act, the title and arms were attainted, and all the vast Baltinglass possessions were forfeited, with retrospective clauses voiding all transfers of property that had taken place during the previous twelve years. The Eustaces of Harristown, once Lords of Portlester, Kilcullen and Baltinglass were thus virtually obliterated. James and his brothers had fought for what they were convinced was right, but they had failed, and for their failure they paid dearly. Whether traitors or martyrs, they were certainly brave men. At the time of the attainder, the Dowager Viscountess, once a proud Butler, but now the mother of " the six traitorous brethren," petitioned (rather pathetically, and with what result we can well imagine) to be allowed to retain her jointure or alternatively to be granted somewhere to live.

Almost all the forfeited estates were granted to Sir Henry Harrington who had been active in quelling the rebellion. He sold them in 1617 to Sir Charles Wilmot, from whom they passed, via Sir James Carroll and Sir Thomas Roper, to the Viscounts (later Earls) of Aldborough. Harristown, Rochestown and Calverstown were granted in about 1590 to John Eustace of Castlemartin with whom we shall deal shortly. The Baltinglass, house in Dublin and a lease of New Abbey, Kilcullen, were granted to Edmund Spenser, the poet, who was Secretary to the Lord Deputy, Lord Arthur Grey de Wilton.

The title Viscount Baltinglass was revived in 1685, when Colonel Richard Talbot, of Carlton, was created Viscount Baltinglass, but he died without an heir six years later. It was again revived in 1763, when John Stratford was created Baron of Baltinglass, but he was advanced in 1776 to Viscount Aldborough and this title became extinct in 1875. The Eustaces of Castlemartin and Harristown were connected with his family twice. His father had married (as his second wife) Penelope nee Eustace, one of the three co-heiresses of Sir Maurice Eustace, the Lord Chancellor. His great-great-granddaughter, Louisa Saunders of Saunders Grove, married in 1860 Thomas Tickell, descendant and heir of Clotilda, Penelope's sister and another of the co-heiresses.

See also Baltinglass Rebellion