The Wexford Martyrs were Matthew Lambert, Robert Myler, Edward Cheevers, Patrick Cavanagh (Irish: Pádraigh Caomhánach), John O'Lahy, and one other unknown individual. In 1581, they were found guilty of treason for aiding in the escape of James Eustace, 3rd Viscount Baltinglass; for refusing to take the Oath of Supremacy which declared Elizabeth I of England to be the head of the Church; and for conveying Catholic priests, laymen, and a Jesuit out of Ireland. On 5 July 1581, they were hanged, drawn and quartered in Wexford, Ireland. They were subsequently Beatified by Pope John Paul II.
In the Pale the predominant religion was Catholic, and the Catholics saw a growing threat from the Protestant-dominated government, a perception supported by their marked decline in participation within the kingdom's government. English-born Protestants increasingly occupied positions of authority. The people of the Pale resented taxes on their property for the government's military policy against the Gaelic lords and rebellious Anglo-Irish. Troops were also billeted upon their lands. James Eustace's father, Viscount Roland, had been imprisoned by the Elizabethan administration for his opposition.
During the summer of 1580, James Eustace, Viscount Baltinglass, apparently prompted almost entirely by religious motives, raised forces in County Wicklow, in support of the Earl of Desmond's separate uprising in Munster. The Viscount's allies included clansmen led by Fiach McHugh O'Byrne. At first the revolt was successful, but Baltinglass did not coordinate his efforts with those of Desmond and could not sustain the conflict. He and his followers were outlawed. Forty-five were hanged in Dublin. James Eustace escaped to Munster, where Desmond was still in revolt. After Desmond was killed he left for Spain.
Pursued by English troops after the collapse of the Second Desmond Rebellion, James Eustace and his chaplain, Father Robert Rochford, eventually found refuge with Matthew Lambert, a Wexford baker. Lambert fed them and arranged with five sailor acquaintances for safe passage by ship for them. Lambert was betrayed, along with sailors Patrick Cavanagh, Edward Cheevers, Robert Myler, John O'Lahy, and one other. They were arrested, imprisoned, and tortured, before being executed in Wexford on 5 July 1581.