Eoghan Rua Ó Néill, anglicised as Owen Roe O'Neill, left Ireland as one of the "Flight of the Earls" in the 17th century. During his time away from his homeland, he fought in the service of the Spanish in the Netherlands during the Eighty Years War the French. Colonel O'Neill led a garrison of Spanish soldiers against the French at the siege of Arras in 1640.

Taking from his military leadership experience gained serving with the Spanish, O'Neill returned to Ireland in 1642 with a force of 300 battle hardened soldiers to force the English out of his homeland. The war he started is today known at the Irish Confederate War. At the outset, the campaigns led by O'Neill were wholly unsuccessful until 1646 when he received supplies and trained soldiers from the Papal, Giovanni Battista Rinuccini. Using these resouces, O'Neill routed the Scottish Covenanter Army commanded by Major General Robert Munro at the battle of Benburb in June of 1646.

O'Neill's victory was short-lived, as members of the Catholic army made treaties with Ormonde. This crushed O'Neill's spirit and he lost his drive to repel Royalist forces any longer. Later, in 1648 he made attempts to regain leadership and link with the armies of the parliamentarians in the north, but had little luck. When Cromwell arrived in August of 1649, O'Neill once more linked with Ormonde and the Catholic confederates, with whom he prepared to co-operate more earnestly in an effort to repel the overwhelming and heinous forces of Cromwell's army.

Before, however, anything was accomplished by this combination, Owen Roe died on 6 November 1649 at Clough Oughter castle in Co Cavan. Some believe he was poisoned by the English, though this has never been proven. It is generally accepted that he died of a disease acquired during his warring days in the Netherlands. He was buried in the dark of the night at a nearby Francisican monestary in Co. Cavan.

INFO: http://www.british-civil-wars.co.uk/biog/oneill.htm