O'Hallaghan, Edmund (Simon of the Holy Spirit) (d. c.1607), Dominican priest, was the son of John O'Hallaghan (Johannis Halychanis) and Elinora Cunt, residents of the parish of St Mary, Youghal (Yohullia). The Irish form of his name in Munster is Ó hAllachacháin and was that of an old family of Co. Cork.
O'Hallaghan entered St Patrick's College (the Irish college), Lisbon, in 1584, the first Irish Dominican known to have studied in Portugal. Before completing his studies for the diocesan priesthood he joined the Portuguese Dominicans in 1591. He appears as ‘Halicano’ on a list of the alumni who had become Dominicans before 1616. He made solemn profession in the order at the Convento São Domingos, Lisbon, on 18 June 1592, when he was given the name in religion ‘Simon of the Holy Spirit’. He received minor orders and the diaconate at Lisbon at the hands of the exiled Franciscan bishop, Conor (or Cornelius) O'Mulrian (Ryan) of Killaloe. His priestly ordination probably followed in 1594. His first attempt to return to Ireland, in 1596, was unsuccessful: he sailed with the ill-fated Spanish fleet of about 100 ships from Lisbon to Ireland in late October at the request of the senior admiral of Castile and the bishop of Killaloe. His ship survived the series of disastrous storms off Cape Finisterre when about thirty ships were lost. O'Hallaghan was reinstated in his convent in Lisbon by royal command. During his sixteen years at Lisbon he received financial aid from its viceroy, the Archduke Albert, and was said to have rendered many services to God and the king, especially in a time of plague, when he was put in pastoral charge of more than 10,000 people and heard sacramental confessions in five languages.
In 1600 he returned to Ireland. According to his own testimony Edmond O'Hallaghan travelled the kingdom, preaching the catholic faith. At Kilkenny he reconciled one of the principal monasteries of his order, the Black Abbey, and had it repaired at a cost of 300 pounds of silver. For this he was summoned before Lord Deputy Mountjoy (qv) and the council of Ireland. He afterwards claimed that he presented his case so well that he persuaded these officials to allow the monastery to remain standing. Contemporary historical sources confirm his strong personality and impressive presence. At Waterford, where he accompanied the leader of the revival, James White, vicar apostolic of Waterford, to Grace Dieu, he engaged Mountjoy in theological debate. At Kilkenny he had the support of two Dominicans, Edmund Barry and Edward Raughter, actively assisted by Sir Walter Archer (d. 1604), sovereign of Kilkenny, who suffered incarceration and continental exile for restoring public catholic worship.
Inspired by these signs of fresh beginnings, O'Hallaghan, ‘vicar general of the Order of St Dominic in Ireland’, returned to Spain, presented himself, with twelve companions (two of whom were Dominicans), at the court in Valladolid, and obtained a notable grant of 2,000 ducats from Philip III (15 December 1604) to cover liturgical, travel, and living expenses of his companions in Ireland. The petitioner was noted as prudent and highly respected in Ireland, and as one who could be relied upon to be of service to the king. He may have been recommended too by James MacDonnell OP, confessor to Philip III.
By 1606 O'Hallaghan was involved in promoting the catholic revival in Limerick. He became principal chaplain to one of its prime instigators, John Burke (qv), whose father had been high sheriff of Limerick in the 1570s. The banqueting hall of Brittas Castle, the Burke family's seat in Co. Limerick, became an important meeting place of catholics for mass and of the Dominican confraternity of the Holy Rosary. Early on the first Sunday of October 1606 the castle was besieged by English soldiers, who dispersed the faithful who had assembled for the mass of the confraternity's patronal festival. Burke was taken prisoner, indicted for treason, imprisoned, and executed, having refused a pardon that was conditional on his renouncing catholicism. Shortly before his execution, Burke sent a letter from prison to O'Hallaghan, director of the confraternity, who had managed to escape, beseeching him to instruct his wife in the catholic faith. This was Grace Thornton, daughter of Sir George Thornton, a Munster land magnate. She was so eager to please her husband that she went from Carrick-on-Suir to Waterford and, failing to find O'Hallaghan there, travelled on to Kilkenny (winter 1606). She afterwards married Turlough, eldest son of the pluralist protestant prelate Miler Magrath (qv), archbishop of Cashel.
Nothing further is heard of O'Hallaghan in Ireland. By early 1607 he had probably left Waterford for Spain on account of the rigorous enforcement of an edict of James I (29 September 1605), banishing all Irish catholic clergy into exile. He may have been the ‘senior father, Simon of the Holy Spirit’ whose death at San Esteban, Salamanca, was recorded in 1607. Although he shone conspicuously in Portugal and Spain, O'Hallaghan's Irish career remains relatively unknown; he was apparently the earliest founding father in the second spring of Hibernia Dominicana, who heralded the energetic, short-lived catholic revival in parts of Leinster and Munster in 1600–07.