He was ordained priest on 1 June, 1833, and appointed professor of sacred scripture in the Irish College, of which he was subsequently vice-rector. In 1834 he returned to Ireland and was made pastor of Fermoy. He was invited by Bishop Kenrick to Philadelphia in 1839 and appointed professor in the ecclesiastical seminary of St. Charles Boromeo, of which he was made president soon afterward. While he discharged the duties of this office he attended the missions of Norristown and West Chester, Pennsylvania, and built the church of St. Francis Xavier in Fairmount.

In 1841 he was transferred to Pittsburg and made vicar-general of the western part of the diocese of Philadelphia. He established schools and reading-rooms, organized the Catholic institute in the parish of St. Paul, of which he was pastor, and built several churches.

He had long desired to become a member of the Society of Jesus, but as a student of the Propaganda he could not take such a step without the consent of the pope. He set out for Rome in 1843 to get the required permission.

Meanwhile the diocese of Pittsburg had been created, his name had been sent forward, and when he knelt before Gregory XVI he was forbidden to rise until he consented to become bishop of the new see, the pope at the same time saying: "You shall be bishop first and Jesuit after." He was consecrated by Cardinal Fransoni on 15 August, went to Ireland, and returned to Pittsburg in December, bringing with him some candidates for the priesthood and Sisters of Mercy.

His diocese had a Roman Catholic population of 25,000 and fourteen priests with only two religious institutions. He held his first diocesan synod in 1844, and the same year opened a church for colored Roman Catholics, established a boys' academy and a seminary for young ladies under the care of the Sisters of Mercy, founded two temperance societies, began to publish the "Catholic," and founded St. Michael's Seminary for the education of candidates for the ministry.

In 1846 he made his first Episcopal visitation and introduced the order of St. Benedict for the first time into the United States. In 1852 he again visited Europe and persuaded a colony of Passionists to return with him, who opened their first house in the United States in Pittsburg. In 1853 he published a series of letters to the governor of Pennsylvania on the common-school system.

The same year the see of Pittsburg was divided and the diocese of Erie was formed from it. Bishop O'Connor was transferred to the new diocese at his own request, but on the petition of the clergy and people of Pittsburg he was sent back by the pope.

He went to Rome in 1854 to take part in defining the dogma of the Immaculate Conception, and it was said that certain alterations in the wording of the decree were due to his advice. In 1855 he finished the Pittsburg cathedral, which is the largest in the United States with two exceptions. Bishop O'Connor was very successful in financial investments. One piece of property that he bought at $16,000 was afterward assessed for $162,000.

In 1860 he was permitted to resign his see, the number of priests in which had then increased to eighty-six and the churches to seventy-seven, he entered a Jesuit monastery in Germany, and by a special, dispensation was allowed to take the usual vows in two years. He then returned to the United States and was appointed professor of theology in Woodstock College, Maryland.

He was afterward socius to the provincial of the Jesuits, and preached and lectured in most of the great cities throughout the United States. He took much interest in the colored people, and, owing to his exertions, St. Xavier's church was opened for them in Baltimore. He was an accomplished linguist.

--His brother, James O’Connor, R. C. bishop, born in Queenstown, Ireland, 10 September, 1823, emigrated to the United States in 1838 and entered the Seminary of St. Charles Borromeo, Philadelphia. He was sent to the Propaganda, Rome, to study philosophy and theology, and completed his course in 1845, when he was ordained priest.

He then returned to this country, and was assigned to missionary duty in the diocese of Pittsburg. He was made president of St. Michael's Seminary, Glenwood, in 1857, and this institution made such progress during his administration that he was obliged to build extensive additions in 1862.

He was transferred to the seminary at Overbrook in 1863, where, while acting as director, he filled the chairs of philosophy, moral theology, and ecclesiastical history, he made a tour of Europe, and on his return was appointed pastor of St. Dominic's Church at Holmesburg, Pennsylvania

He was nominated vicar-apostolic of Nebraska, and consecrated bishop of Dibona in parlibus infidelium on 20 August, 1876. He introduced the Jesuits and Franciscans into the vicariate, and opened Creighton College in 1879. In 1885 the vicariate was erected into a regular see. It contained in 1887 about eighty-seven priests, thirteen chapels, and various religious and educational institutions.

O'CONNOR, Michael, R. C. bishop, born near Cork, Ireland, 27 September, 1810; died in Woodstock, Maryland, 18 October, 1872. He received his preparatory education in Queenstown, was sent in 1824 to an ecclesiastical seminary in France, and finished his theological course in the College of the propaganda, Rome. He won his doctor's cap in a public disputation that was long remembered for its brilliancy, and Cardinal Wiseman, who was then in Rome, predicted a great career for him. He was ordained priest on 1 June, 1833, and appointed professor of sacred scripture in the Irish college, of which he was subsequently vice-rector. In 1834 he returned to Ireland and was made pastor of Fermoy. He was invited by Bishop Kenrick to Philadelphia in 1839 and appointed professor in the ecclesiastical seminary of St. Charles Boromeo, of which he was made president soon afterward. While he discharged the duties of this office he attended the missions of Norristown and West Chester, Pennsylvania, and built the church of St. Francis Xavier in Fairmount. In 1841 he was transferred to Pittsburg and made vicar-general of the western part of the diocese of Philadelphia. He established schools and reading-rooms, organized the Catholic institute in the parish of St. Paul, of which he was pastor, and built several churches, he had long desired to become a member of the Society of Jesus, but as a student of the Propaganda he could not take such a step without the consent of the pope. He set out for Rome in 1843 to get the required permission. Meanwhile the diocese of Pittsburg had been created, his name had been sent forward, and when he knelt before Gregory XVI. he was forbidden to rise until he consented to become bishop of the new see, the pope at the same time saying: "You shall be bishop first and Jesuit after." He was consecrated by Cardinal Fransoni on 15 August, went to Ireland, and returned to Pittsburg in December, bringing with him some candidates for the priesthood and Sisters of Mercy. His diocese had a Roman Catholic population of 25,000 and fourteen priests with only two religious institutions. He held his first diocesan synod in 1844, and the same year opened a church for colored Roman Catholics, established a boys' academy and a seminary for young ladies under the care of the Sisters of Mercy, founded two temperance societies, began to publish the "Catholic," and founded St. Michael's seminary for the education of candidates for the ministry. In 1846 he made his first episcopal visitation and introduced the order of St. Benedict for the first time into the United States. In 1852 he again visited Europe and persuaded a colony of Passionists to return with him, who opened their first house in the United States in Pittsburg. In 1853 he published a series of letters to the governor of Pennsylvania on the common-school system. The same year the see of Pittsburg was divided and the diocese of Erie was formed from it. Bishop O'Connor was transferred to the new diocese at his own request, but on the petition of the clergy and people of Pittsburg he was sent back by the pope. He went to Rome in 1854 to take part in defining the dogma of the immaculate conception, and it was said that certain alterations in the wording of the decree were due to his advice. In 1855 he finished the Pittsburg cathedral, which is the largest in the United States with two exceptions. Bishop O'Connor was very successful in financial investments. One piece of property that he bought at $16,000 was afterward assessed for $162,000. In 1860 he was permitted to resign his see, the number of priests in which had then increased to eighty-six and the churches to seventy-seven, he entered a Jesuit monastery in Germany, and by a special, dispensation was allowed to take the usual vows in two years. He then returned to the United States and was appointed professor of theology in Woodstock college, Maryland. He was afterward socius to the provincial of the Jesuits, and preached and lectured in most of the great cities throughout the United States. He took much interest in the colored people, and, owing to his exertions, St. Xavier's church was opened for them in Baltimore. He was an accomplished linguist.--His brother, James, R. C. bishop, born in Queenstown, Ireland, 10 September, 1823, emigrated to the United States in 1838 and entered the Seminary of St. Charles Borromeo, Philadelphia. He was sent to the Propaganda, Rome, to study philosophy and theology, and completed his course in 1845, when he was ordained priest. He then returned to this country, and was assigned to missionary duty in the diocese of Pittsburg. He was made president of St. Michad's seminary, Glenwood, in 1857, and this institution made such progress during his administration that he was obliged to build extensive additions in 1862. He was transferred to the seminary at Over-brook in 1863, where, while acting as director, he filled the chairs of philosophy, moral theology, and ecclesiastical history, he made a tour of Europe, and on his return was appointed pastor of St. Dominic's church at Holmesburg, Pennsylvania He was nominated vicar-apostolic of Nebraska, and consecrated bishop of Dibona in parlibus infidelium on 20 August, 1876. He introduced the Jesuits and Franciscans into the vicariate, and opened Creighton college in 1879. In 1885 the vicariate was erected into a regular see. It contained in 1887 about eighty-seven priests, thirteen chapels, and various religious and educational institutions.