The dedicatory letter makes reference to one of the most dramatic events in the history of the Oxford Movement. In the 1840s, Newman came under the censure of many of the Anglican bishops of England for his Catholic interpretation of the 39 Articles, the so-called Tract 90. This condemnation was to reach its zenith with the formal condemnation of the Tract by the Convocation of Oxford University. However, just before the vote of Convocation on the issue was to be taken, the two Proctors (Church was the Junior Proctor) exercised their ancient (and rarely exercised) veto on the motions put before Convocation. The drama is described as follows in Ward's history of the Oxford Movement:
“A full Convocation at Oxford,” says a contemporary writer, “is an imposing spectacle. The theatre, one of Wren’s noblest works, with its rostra and semicircular galleries, is admirably adapted to enable a large assembly to see and be seen, and to hear a person speaking from one of the rostra .though it would be unsuited to a debate in which men spoke from their places. It is fit for its purposes—solemn proceedings and set speeches. On the 13th of February  it must have contained fifteen hundred persons, for nearly twelve hundred voted, and the neuters must have exceeded three hundred.”Newman had already retired to Littlemore from University and pastoral life at this stage. He would be received into the Catholic Church later in 1845.
“When the whole assembly,” writes Dean Stanley, “was crowded within the theatre, packed as closely as the area of that splendid building would permit, the Registrar of the University read out the incriminating passages of The Ideal of a Christian Church. (Zadok's note: This book was by Ward.) Grown wiser, and we may add, more just, by the experience of the attack on Dr. Hampden, they did not condemn the whole book, but certain extracts which were chosen from it. The general proceedings were in Latin, but it was curious to hear the grave voice of the Registrar proclaiming in the vernacular from his high position these several sentences [from the book]— 'Oh, most joyful! most wonderful! most unexpected sight! We find the whole cycle of Roman doctrine gradually possessing numbers of English Churchmen!’ Once again the English language was permitted to be heard in that assembly; the Vice-Chancellor rose in his place and announced in Latin that by permission of the Chancellor, to Mr. Ward, and to Mr. Ward alone, was to be given the privilege of using in his own defence his native tongue. Then followed the apology for the book, at that time known in its every part, now probably become one of the obsolete curiosities of literature. It consisted of an effective address, challenging all parties in the Church equally to vindicate their subscription to the Thirty-nine Articles, and calling upon him who was without fault to throw the first stone.”
The speech over, the Vice-Chancellor put the question. There was a roar and counter-roar of “placets” and “non-placets.” A scrutiny was then ordered, and the first resolution—the censure of the passages from the Ideal—was carried by 777 to 391; the second—the degradation—by a much smaller majority, 569 to 511. Then came the proposal for the condemnation of Tract 90. The Vice-Chancellor read the resolution. But now the two Proctors rose, Mr. Guillemard and Mr. Church, and uttered the words which, except on one memorable occasion, the Hampden case, no one living had ever heard pronounced in Convocation. When the resolution was put, a shout of “non” was raised, and resounded through the whole building, and “placets” from the other side, over which Guillemard’s “nobis Procuratoribus non-placet” was heard like a trumpet and cheered enormously. The Dean of Chichester threw himself out of his doctor’s seat and shook both Proctors violently by the hand, and, without any formal dissolution, indeed, without a word more being spoken, as if such an interposition as the Proctor’s veto stopped all business, the Vice-Chancellor tucked up his gown, and hurried down the steps that led from his throne into the area, and hurried out of the theatre; and in five minutes the whole scene of action was cleared. Mr. Ward was cheered by the undergraduates as he left the theatre, and the Vice-Chancellor was saluted by hisses and snowballs from the same quarter.
It was noticed that Mr. Gladstone’s non-placet was peculiarly vehement. He voted in Mr. Ward’s favour on both propositions. All the Fellows of Balliol without exception supported Mr. Ward likewise in both votes.
It should be noted that in 1871, Newman was still a controversial person in Catholic and Protestant circles, thus explaining the delicacy of Newman's dedication to Church:
VERY REV. RICHARD WILLIAM CHURCH, M.A.
DEAN OF ST. PAUL'S
MY DEAR DEAN,
WHEN I lately asked your leave to prefix your name to this Volume of Sermons preached before the University of Oxford, I felt I had to explain to myself and to my readers, why I had not offered it to you on its first publication, rather than now, when the long delay of nearly thirty years might seem to have destroyed the graciousness of my act.
For you were one of those dear friends, resident in Oxford, (some, as Charles Marriott and Charles Cornish now no more,) who in those trying five years, from 1841 to 1845, in the course of which this Volume was given to the world, did so much to comfort and uphold me by their patient, tender kindness, and their zealous services in my behalf.
I cannot forget, how, in the February of 1841, you suffered me day after day to open to you my anxieties and plans, as events successively elicited them; and much less can I lose the memory of your great act of friendship, as well as of justice and courage, in the February of 1845, your Proctor's year, when you, with another now departed, shielded me from the "civium ardor prava jubentium," by the interposition of a prerogative belonging to your academical position.
But much as I felt your generous conduct towards me at the time, those very circumstances which gave occasion to it deprived me then of the power of acknowledging it. That was no season to do what I am doing now, when an association with any work of mine would have been a burden to another, not a service; nor did I, in the Volumes which I published during those years, think of laying it upon any of my friends, except in the case of one who had had duties with me up at Littlemore, and overcame me by his loyal and urgent sympathy.
Accept then, my dear Church, though it be late, this expression of my gratitude, now that the lapse of years, the judgment passed on me by (what may be called) posterity, and the dignity of your present position, encourage me to think that, in thus gratifying myself, I am not inconsiderate towards you.
I am, my dear Dean,
Your very affectionate friend,
JOHN H. NEWMAN.