Denvir, Cornelius (1791–1866), catholic bishop of Down and Connor, was born on 13 August 1791 in the townland of Ballywalter, Co. Down, about four miles from Downpatrick. His parents' names are not recorded. He was educated at local schools and at the classical school in Downpatrick, which was conducted by Dr James Neilson (1768-1838), the presbyterian minister of the town. Thence he passed to Maynooth College in September 1808, and six years later, after a distinguished course, was ordained priest. A year before his ordination he had been appointed temporary lecturer in natural philosophy (science) and remained in the college, becoming professor of that subject in 1815. For three years he also taught church music. In 1826 he was appointed parish priest of Downpatrick, but was asked to combine that office with teaching classics and mathematics in St Malachy's College, Belfast, which opened as a minor seminary and secondary boys' school in 1833. Two years later he was the almost unanimous choice of the parish priests of Down and Connor for the bishopric of the diocese, when Bishop William Crolly (qv) was transferred to Armagh. He was duly appointed and ordained bishop on 22 November 1835.
Since 1825 the bishop of Down and Connor had lived in the rapidly growing town of Belfast, which was then served by two churches. In 1841 Denvir laid the foundation stone of the third, St Malachy's, but found the labour of fund-raising very difficult. He was even briefly arrested as a debtor when money was not available to pay the contractor, and was badly shaken by that experience. He encountered similar difficulties in providing a convent for the Sisters of Mercy, who came to Belfast in 1854, and was reluctant to take on further building projects. But as the catholic population was increasing enormously – from approximately 23,500 in 1841 to about 29,000 in 1851 and 41,500 in 1861 – Denvir was criticised for not equipping the catholic community with more churches and priests. Political hostilities and sectarian disturbances added to his problems. In the early 1840s he supported repeal. When Daniel O'Connell (qv) visited Belfast in 1841, Henry Cooke (qv), the presbyterian leader, led the resistance to his campaign, and rioting followed. Serious riots fuelled by sectarian animosity also occurred in Belfast in 1857 and 1864, and in other years minor disorders broke out.
Denvir continued his predecessor's policy of serving on committees devoted to public welfare, and of publishing cheap catholic versions of the bible. In 1851, to celebrate Queen Victoria's visit to Belfast two years earlier, he organised a display of electric light.
During the 1840s the hierarchy was split on three important issues. The first concerned the religious safety of catholic children in the national school system, which had been established in 1831 to make education widely available through combined classes for moral and literary instruction, and separate classes for religious instruction. Archbishop John MacHale (qv) of Tuam and a minority of the bishops opposed the system. Denvir was among the ‘liberals’ who favoured it and who, with certain safeguards, were allowed by the Vatican to make use of it. A similar split occurred over legislation to regulate charitable bequests. Some bishops objected to the rules whereby bequests of land or property made for charitable purposes within three months of the testator's death, or those made to religious orders, were not valid. Denvir again took the ‘liberal’ side and accepted appointment as a commissioner of bequests. Similarly he was among the smaller minority which was prepared to work the queen's colleges, the system of university education denounced by O'Connell and its opponents as ‘godless’. The Vatican, however, in 1847 and 1848 condemned the colleges and called for the establishment of a catholic university.
As a result of the representations made to Rome by Archbishop Paul Cullen (qv) of Dublin and Archbishop Joseph Dixon (qv) of Armagh about the need for an energetic bishop who would deal more effectively with the pastoral problems of Belfast and would provide more schools for catholic children, a coadjutor with right of succession was appointed in 1860. Denvir was later persuaded by the two archbishops and the Vatican to retire, and he did so in May 1865. He died on 10 July 1866.