In 1516 a scholar in Basel raced a Greek New Testament into print to beat a rival edition. He called it thrown together rather than edited. Four centuries of English Bibles inherited it anyway.
In Spain, Cardinal Jiménez de Cisneros had been assembling the Complutensian Polyglot since 1502: six volumes, Greek beside Hebrew and Latin, done slowly and done properly. Its New Testament volume was printed in 1514. Then it sat, waiting for papal sanction it would not receive for years.
The printer Johann Froben saw the gap. If a Greek New Testament could be got out of Basel before the Spanish volumes were released, it would be the first in print. He put the work to Erasmus in 1515. It was published in March 1516.
Erasmus knew exactly what he had produced. He described the edition in a letter as praecipitatum verius quam editum - thrown together rather than edited. That is not a critic's verdict. It is the editor's.
Erasmus worked from what Basel could lend him: six or seven Greek manuscripts, none earlier than the eleventh century, most of them twelfth. For the Gospels he leaned on one twelfth-century copy. He did not have and could not have had the fourth-century codices that anchor a modern edition. Vaticanus sat in Rome, effectively unconsulted; Sinaiticus would not be found for another three hundred years.
For Revelation he had a single manuscript. Its final leaf was missing.
That last fact is the one that matters, because of what he did about it.
The readings this edition handed to the English Bible are usually listed together, as though one mistake produced them. They are three different kinds of problem and the differences are the whole story.
Mark 16:9-20 - the resurrection appearances, the snake handling, the promise about poison. It is not an Erasmian invention. It stands in the great majority of later Greek manuscripts and every copy on his desk had it. He printed what he was given.
The problem is age, not authorship. The two oldest complete Bibles, Sinaiticus and Vaticanus, both end at 16:8, with the women saying nothing to anyone because they were afraid. Erasmus had no way to know that. His fault here is only that he could not see past the eleventh century.
1 John 5:7-8, the Comma Johanneum: "the Father, the Word and the Holy Ghost: and these three are one." The only sentence in the New Testament that states the Trinity outright.
It is not in the 1516 edition. It is not in the 1519 second edition either. Erasmus left it out because no Greek manuscript he had contained it - it lived in the Latin tradition. He was attacked for the omission.
It appears in the third edition of 1522, after a Greek manuscript containing it was produced in England. That manuscript, now Codex Montfortianus in Dublin, appears to have been copied around 1520 - which is to say, after the argument started. Whether Erasmus had promised to include the verse if a manuscript could be found is disputed among scholars; that he printed it under pressure is not.
This one is his own. The last leaf of his only Revelation manuscript was missing, so for the closing verses he took the Latin Vulgate and translated it back into Greek.
At Revelation 22:19 the Greek manuscripts read that God will take away a man's share in the tree of life - xylou. The Latin had libro, book. Erasmus rendered the Latin back as biblou and printed a reading that exists in no Greek manuscript anywhere.
It is in the King James Version. "God shall take away his part out of the book of life."
Nobody ever decided this text was correct. It became standard because it was first, then because it was familiar and finally because it had a Latin name that sounded like a verdict.
Open a modern translation at 1 John 5:7 and the Trinity formula is gone, or in a footnote. Mark 16:9-20 sits behind a line saying the earliest manuscripts do not have it. Readers notice and reasonably ask who removed them.
Nobody did. The verses were never being removed - they were being declined. A modern critical text is built from manuscripts Erasmus never saw, some of them a thousand years older than his. Where those manuscripts do not support a reading, it is not printed as scripture.
The King James is not the baseline that later Bibles departed from. It is one printed tradition among several and it descends from six or seven late manuscripts borrowed in a hurry in Basel.
Erasmus was not a forger and not a fool. He was a first-rate humanist working at printer's speed with the only manuscripts within reach and he said plainly what the result was worth. Almost everything in his text is the ordinary Byzantine reading and almost all of it is fine.
What went wrong happened after him. A provisional edition, produced to win a race, was reprinted until it hardened, given a name that implied consent and treated for four hundred years as the thing the manuscripts said. The failure is not one scholar's haste. It is what a culture does with a text once it stops asking where it came from.