At Trinity the effect of the tractarian movement was to lead some adherents to the study of history in order, in the first instance, to maintain the historical position and claims of the church.
Having been ordained deacon on his fellowship in 1840, he acted for about a year as curate of the church of St. Mary the Virgin, Oxford, to John Henry Newman.
He was Dean of Trinity College for several years and afterwards vice-president, and was pro-proctor to Henry Peter Guillemard when in 1845 the proctors put their veto on the proceedings against Newman.
The judgment on the Gorham case in 1850 troubled him, and for a while he doubted whether he could conscientiously accept a benefice; he found satisfaction through studying the foundation of the Church of England's claims.
Early in 1869 he brought out, in conjunction with William Stubbs, the first volume of the major work, Councils and Ecclesiastical Documents, founded on the collections of Henry Spelman and David Wilkins.
The part of this volume which is devoted to the early Irish church, and required research into language as well as history, occupied him during his last days.