Bull had been ordained at twenty-one; he was consecrated, in 1705, Bishop of St. Davids, at the almost equally exceptional age of seventy. He succeeded a bad man who had been expelled from his see for glaring simony; and it was felt, not without justice, that the cause of religion and the honour of the Episcopate would gain more by the elevation of a man of the high repute in which Bull was universally held, than it would lose by the growing infirmities of his old age. He accepted the dignity with hesitation, in hopes that his son, the Archdeacon of Llandaff, who however died before him, would be able greatly to assist him in the discharge of his duties. But as he was determined that if he could not be as active as he would wish, he would at all events reside strictly in his diocese, he saw little or no more of his friend Nelson, of whom he had said that 'he scarce knew any one in the world for whom he had greater respect and love.'[64] During the first four years of the century there had been a frequent correspondence between them on the subject of his controversy with Bossuet, with whom Nelson had long been in the habit of interchanging friendly courtesies. The Bishop of Meaux had written, in 1700, to Nelson, expressing admiration of Bull's work on the Trinity, and wonder as to what he meant by the term 'Catholic,' and why it was that, having such respect for primitive antiquity, he remained nevertheless separated from the unity of Rome. Bull wrote in answer his 'Corruptions of the Church of Rome,' and sent the manuscript of it to Nelson in 1704. It did not, however, reach Bossuet, who died that year. Bishop Bull followed him in 1709.