Some translations of the lesser works of Plutarch were published by Froben in August. The Adagia was passing through the press again with corrections and additions, and the preface which was originally destined for Badius. At the same time Dirck Maertensz, at Louvain, was also at work for Erasmus, who had, on passing through the town, entrusted him with a collection of easy Latin texts; also M. Schürer at Strassburg, who prepared the Parabolae sive similia for him. For Froben, too, Erasmus was engaged on a Seneca, which appeared in 1515, together with a work on Latin construction. But Jerome and the New Testament remained his chief occupation.

Jerome's works had been Erasmus's love in early youth, especially his letters. The plan of preparing a correct edition of the great Father of the Church was conceived in 1500, if not earlier, and he had worked at it ever since, at intervals. In 1513 he writes to Ammonius: 'My enthusiasm for emending and annotating Jerome is such that I feel as though inspired by some god. I have almost completely emended him already by collating many old manuscripts. And this I do at incredibly great expense.' In 1512 he negotiated with Badius about an edition of the letters. Froben's partner, Johannes Amerbach, who died before Erasmus's arrival, had been engaged for years on an edition of Jerome. Several scholars, Reuchlin among others, had assisted in the undertaking when Erasmus offered himself and all his material. He became the actual editor. Of the nine volumes, in which Froben published the work in 1516, the first four contained Erasmus's edition of Jerome's letters; the others had been corrected by him and provided with forewords.

His work upon the New Testament was, if possible, still nearer his heart. By its growth it had gradually changed its nature. Since the time when Valla's Annotationes had directed his attention to textual criticism of the Vulgate, Erasmus had, probably during his second stay in England from 1505 to 1506, at the instance of Colet, made a new translation of the New Testament from the Greek original, which translation differed greatly from the Vulgate. Besides Colet, few had seen it. Later, Erasmus understood it was necessary to publish also a new edition of the Greek text, with his notes. As to this he had made a provisional arrangement with Froben, shortly after his arrival at Basle. Afterwards he considered that it would be better to have it printed in Italy, and was on the point of going there when, possibly persuaded by new offers from Froben, he suddenly changed his plan of travel and in the spring of 1515 made a short trip to England—probably, among other reasons, for the purpose of securing a copy of his translation of the New Testament, which he had left behind there. In the summer he was back at Basle and resumed the work in Froben's printing-office. In the beginning of 1516 the Novum Instrumentum appeared, containing the purified Greek text with notes, together with a Latin translation in which Erasmus had altered too great deviations from the Vulgate.

From the moment of the appearance of two such important and, as regards the second, such daring theological works by Erasmus as Jerome and the New Testament, we may say that he had made himself the centre of the scientific study of divinity, as he was at the same time the centre and touchstone of classic erudition and literary taste. His authority constantly increased in all countries, his correspondence was prodigiously augmented.

But while his mental growth was accomplished, his financial position was not assured. The years 1515 to 1517 are among the most restless of his life; he is still looking out for every chance which presents itself, a canonry at Tournay, a prebend in England, a bishopric in Sicily, always half jocularly regretting the good chances he missed in former times, jesting about his pursuit of fortune, lamenting about his 'spouse, execrable poverty, which even yet I have not succeeded in shaking off my shoulders'. And, after all, ever more the victim of his own restlessness than of the disfavour of fate. He is now fifty years old and still he is, as he says, 'sowing without knowing what I shall reap'. This, however, only refers to his career, not to his life-work.

In the course of 1515 a new and promising patron, John le Sauvage, Chancellor of Brabant, had succeeded in procuring for him the title of councillor of the prince, the youthful Charles V. In the beginning of 1516 he was nominated: it was a mere title of honour, promising a yearly pension of 200 florins, which, however, was paid but irregularly. To habilitate himself as a councillor of the prince, Erasmus wrote the Institutio Principis Christiani, a treatise about the education of a prince, which in accordance with Erasmus's nature and inclination deals rather with moral than with political matters, and is in striking contrast with that other work, written some years earlier, il Principe by Machiavelli.

When his work at Basle ceased for the time being, in the spring of 1516, Erasmus journeyed to the Netherlands. At Brussels he met the chancellor, who, in addition to the prince's pension, procured him a prebend at Courtray, which, like the English benefice mentioned above, was compounded for by money payments. At Antwerp lived one of the great friends who helped in his support all his life: Peter Gilles, the young town clerk, in whose house he stayed as often as he came to Antwerp. Peter Gilles is the man who figures in More's Utopia as the person in whose garden the sailor tells his experiences; it was in these days that Gilles helped Dirck Maertensz, at Louvain, to pass the first edition of the Utopia through the press. Later Quentin Metsys was to paint him and Erasmus, joined in a diptych; a present for Thomas More and for us a vivid memorial of one of the best things Erasmus ever knew: this triple friendship.

In the summer of 1516 Erasmus made another short trip to England. He stayed with More, saw Colet again, also Warham, Fisher, and the other friends. But it was not to visit old friends that he went there. A pressing and delicate matter impelled him. Now that prebends and church dignities began to be presented to him, it was more urgent than ever that the impediments in the way of a free ecclesiastical career should be permanently obviated. He was provided with a dispensation of Pope Julius II, authorizing him to accept English prebends, and another exempting him from the obligation of wearing the habit of his order. But both were of limited scope, and insufficient. The fervent impatience with which he conducted this matter of his definite discharge from the order makes it probable that, as Dr. Allen presumes, the threat of his recall to Steyn had, since his refusal to Servatius in 1514, hung over his head. There was nothing he feared and detested so much.

With his friend Ammonius he drew up, in London, a very elaborate paper, addressed to the apostolic chancery, in which he recounts the story of his own life as that of one Florentius: his half-enforced entrance to the monastery, the troubles which monastic life had brought him, the circumstances which had induced him to lay his monk's dress aside. It is a passionate apology, pathetic and ornate. The letter, as we know it, does not contain a direct request. In an appendix at the end, written in cipher, of which he sent the key in sympathetic ink in another letter, the chancery was requested to obviate the impediments which Erasmus's illegitimate birth placed in the way of his promotion. The addressee, Lambertus Grunnius, apostolic secretary, was most probably an imaginary personage.[14] So much mystery did Erasmus use when his vital interests were at stake.

The Bishop of Worcester, Silvestro Gigli, who was setting out to the Lateran Council, as the envoy of England, took upon himself to deliver the letter and to plead Erasmus's cause. Erasmus, having meanwhile at the end of August returned to the Netherlands, awaited the upshot of his kind offices in the greatest suspense. The matter was finally settled in January 1517. In two letters bearing the signature of Sadolet, Leo X condoned Erasmus's transgressions of ecclesiastical law, relieved him of the obligation to wear the dress of his order, allowed him to live in the world and authorized him to hold church benefices in spite of any disqualifications arising from illegitimacy of birth.