Matthews (MacMahon), Eugene (Eoin) (c.1575–1623), catholic archbishop of Dublin, was the son of Brian MacMahon (Ever Mac Con Uladh MacMahon) of Farney, Co. Monaghan, and his wife Nora Nyne Caalan. He was sent at a young age to be educated at Pont-à-Mousson in the Spanish Netherlands and became a highly accomplished scholar. About 1599 he went to Salamanca to study theology, and eventually gained a doctorate in civil and canon law, possibly from Salamanca. In 1606 he appears in Germany, at which time he was close to becoming bishop of Clogher. By 1607 he was in the Spanish Netherlands again, where he mostly remained for the next six years. An Irish regiment had been created in the Spanish army there and the territory became a magnet for exiled Irish catholics. In autumn 1607 he met with Hugh O'Neill (qv), earl of Tyrone, and with Ruaidhrí O'Donnell (qv), earl of Tyrconnell, at Douai immediately after their flight from Ireland; he had supported Tyrone's rebellion against the English from 1594 to 1603, regarding it as a catholic crusade against the heretical English monarch, and now supported Tyrone's efforts to secure Spanish military intervention in Ireland. He enjoyed a close relationship with Tyrone's son Henry O'Neill.
In the Spanish Netherlands, Matthews became the head of a small but influential group of exiles that strongly opposed English rule in Ireland. The power and conspiratorial nature of this group was resented by the more moderate Anglo-Norman catholic exiles, who labelled them the ‘northern clique’ because Matthews and his associates were all Gaelic Irish from Ulster or Connacht. Through Tyrone's support, Matthews was made bishop of his home diocese of Clogher on 31 August 1609 and was then translated to the archbishopric of Dublin on 2 May 1611. These appointments infuriated the more moderate Irish catholics and sparked a bout of intensified persecution of catholics in Ireland. Matthews was awake to the dangers he would face in Ireland and successfully petitioned the pope to allow him to use a portable altar in case he needed to make a quick escape.
Matthews returned to Ireland towards the end of 1613. The protestant authorities knew of his militant reputation and the king explicitly ordered the lord deputy, Sir Arthur Chichester (qv), to capture him. The government spread slanders against him, perhaps in an attempt to play on the suspicions harboured by the Leinster catholic clergy towards an outsider originally from Ulster. In March 1614 Chichester wrote of his frustration at not being able to take him, and three years later a reward of £500 was offered for his capture, dead or alive. Matthews showed great courage in coming to Ireland to carry out his office, but his fugitive existence seriously hampered his ability to perform his spiritual functions. Indeed, his experiences in Ireland largely confirmed the warning of the archbishop of Armagh, Peter Lombard (qv), that supporters of Tyrone should not be advanced to Irish sees as they would achieve little, being subject to constant government harassment.
Matthews's one great success was the provincial synod convened at Kilkenny on 22–7 June 1614, at which the assembled clergy professed their continuing allegiance to the papacy, accepted all that had been agreed at the council of Trent (1545–63), empowered bishops to enforce discipline among the clergy, promised not to engage in political affairs, and renewed their commitment to instruct the faithful in the doctrines of the church. He left Ireland for good in 1621 or 1622; by 21 September 1622 he was at Louvain, where on that day he granted a bursary for one student of the Clogher diocese and two bursaries for students of the Dublin archdiocese to study for the priesthood. He reached Rome by 31 December 1622, and on 10 January 1623 he petitioned the congregation of Propaganda Fide for further support for students at Louvain, which led to the funding of six bursaries. On 4 February he presented to Propaganda Fide a report on the state of the Roman catholic faith in Ireland: he described the history of the catholic church in Ireland, detailed the difficulties which the church then faced from the authorities, and presented his ideas on how to preserve the faith. In particular, he called for the establishment of a seminary for the training of Irish students. This committed counter-reformation bishop died in Rome on 1 September 1623, and was buried at the church of S. Pietro in Montorio. In December 1624 Pope Urban VIII established the Irish pastoral college at Louvain.