Similarly to St. Polycarp of Smyrna, Bishop Ó Duibheannaigh was in his eighties when he was hanged, drawn and quartered outside the walls of Dublin.
In September 1992, he was formally beatified by Pope John Paul II as one of the 24 officially recognized Irish Catholic Martyrs.
[3] While in Rome, Ó Duibheannaigh was appointed Bishop of Down and Connor by Pope Gregory XIII on 27 April 1582, and consecrated by Cardinal Nicolas de Pellevé on 2 February 1583.
[citation needed] On 28 January 1612, Bishop Ó Duibheannaigh was tried for high treason, found guilty by the majority of a packed jury, and sentenced to hanging, drawing and quartering on 1 February (Julian Calendar).
Following his trial and sentencing, according to Philip O'Sullivan Beare, a pious Catholic woman who carried food to the imprisoned Bishop asked about his health.
"Pray let me be", he answered, "the viceroy's messenger to me here present, could tell that I might have life and revenue for going once to that temple", pointing to the tower of a Church of Ireland parish.
[6] On 27 September 1992, Ó Duibheannaigh, with sixteen others, the Irish Catholic Martyrs, was beatified by Pope John Paul II in Rome.