In 1505 Desiderius Erasmus published Lorenzo Valla's annotations on the New Testament, stressing in his preface the indispensability of philology for a proper understanding of Scripture.

The return this heralded to the original Greek of the New Testament opened one of the avenues to the revolutionary movement we know as the Protestant Reformation. In 1516 Erasmus brought out the first printed edition of the Greek New Testament, together with his own Latin translation. It was a rushed job. There were too many misprints, which laid him open to the mockery that is customary on the part of critics who could not have begun to do anything half as adventurous themselves. The real challenge, however, was to the status of the Vulgate: the New Testament, for all intents and purposes, was a Latin text and sacrosanct.

Of course, this emphasis on scholarship was nothing new. Lorenzo Valla, the Italian Renaissance humanist, born at Rome about 1407, a priest, is most famous as one of the scholars who demonstrated the fraudulence of the Donation of Constantine: the document fabricated in the late eighth century purporting to legitimate the claims of the papacy. His ridicule of the Latin New Testament brought him into conflict with ecclesiastical authorities on several occasions. However, he died at Rome in 1457, having spent the last decade as a member of the Curia, favoured by Pope Nicholas V, a compulsive bibliophile, who bequeathed some 1,200 Greek and Latin MSS to the Vatican Library.

Eventually, no doubt, Renaissance humanism would have led to reforming the Church. But, when Erasmus came on the scene, the renewal of Greek studies was widely perceived by theologians as a threat to the authority of the Latin Church as a whole.

Born between 1464 and 1469 (he was unsure when), probably in Gouda rather than in Rotterdam (as he claimed), the natural son of a local dignitary and a medical doctor's daughter, Gerrit Gerrits changed his name to Erasmus, prefixing it later with Desiderius, supposedly a Latinization of Erasmus. An Augustinian Canon, ordained priest in 1492, he soon obtained his superiors’ permission to leave the monastery (near Gouda) to study the classics and Greek patristic literature, first at Paris, then in England, where he became friendly with John Colet, Dean of St Paul’s, and Thomas More, future Lord Chancellor and saint. While a guest in More's household Erasmus wrote his most famous work, Praise of Folly, a scathing satire on scholastic theologians, avaricious clergy, mendacious friars, superstitious peasants and suchlike. Erasmus was attracted to Cambridge by John Fisher, Bishop of Rochester and Chancellor of the University, among the greatest scholars of the day and another canonized saint.

Refusing for years to take sides for or against Martin Luther, the Augustinian Hermit, some fifteen years his junior, Erasmus finally gave into pressure but chose to write his De libero arbitrio(1524), defending the dignity and liberty of the human will which he must have guessed would provoke Luther to reply, in his De servo arbitrio, with such vehemence that no reconciliation of views was possible.

Erasmus moved from one university to another. At Louvain the Dominicans and the Franciscans, united for once, opposed him. The theologians at Paris censured some of his works, mostly after his death. In 1590 his works were placed on the Index in toto: many remained banned until the 1960s. Pope Paul III (another Renaissance pope, patron of Michelangelo) seems to have dangled a cardinal's hat in the hope that Erasmus would help in his plans (not that they came to anything) to reform the Church so as to head off further division; but Erasmus declined. Long since dispensed from wearing monastic dress, settled in Freiburg im Breisgau and finally in Basle, he died in 1536. He left a small fortune, in trusts for the benefit of the aged and infirm, the education of young men of promise, and as marriage portions for deserving young women – nothing, however, for Masses for the repose of his soul.

As Simon Goldhill notes, in his splendid book Love, Sex and Tragedy: Why Classics Matter(John Murray 2004, now in paperback), it is difficult to overstate how much was at stake in this return to the original Greek of the New Testament in which such a key part was played by Erasmus. As an edition of the New Testament, his work has no critical value, even by Renaissance standards. But it was the text that first revealed the fact that the Vulgate, the Holy Book of the Latin Church, was not only a second‐hand document but, in places, quite erroneous. Much else was of course involved; but this return to the original Greek text, and the stubborn attempts to discredit it, were critical in bringing on the Reformation. Scholarship should never be underestimated.