John Aubrey in his Brief Lives fleshes out the man behind the scholar:
His name was Gerard Gerard, which he translated into Desiderius Erasmus. Of Roterdam: he loved not Fish, though borne in a Fish-towne.

He was begot (as they say) behind dores. His father tooke great care to send him to an excellent Schoole, which was at Dusseldorf, in Cleveland. He was a tender Chitt, and his mother would not entruste him at board, but tooke a house there, and made him cordialls.

...

He studied sometime in Queens Colledge in Cambridge: his chamber was over the watter. he mentions his being there in one of his Epistles, and blames the Beere1 there.

...

...but I see that the Sun and Aries being in the second house, he was not borne to be a rich man.

John Dreydon, Esq, Poet Laureat, tells me that there was a great friendship between his great-grandfather's father and Erasmus Roterodamus, and Erasmus was godfather to one of his sonnes, and the Christian name of Erasmus hath been kept in the family ever since. The Poet's second sonne is Erasmus.

They were wont to say the Erasmus was Interdependent between Heaven and Hell, till, about the year 1655, the Conclave at Rome damned him for a Heretique, after he had been dead 120 yeares.

The deepest divinity is where a man would least expect it: viz. in his Colloquies in a Dialogue between a Butcher and a Fishmonger.

Julius Scaliger contested with Erasmus, but gott nothing by it, for, as Fuller2 sayth, he was like a Badger, that never bitt but he made his teeth meet.

He was the Προδρομος3 of our knowledge, and the man that made the rough and untrodden wayes smooth and passable.

Notes.
1. 'Blames' here = 'criticizes; says is ill-kept': it doesn't of course mean he blamed the beer for his being in Cambridge; the pubs weren't that good.
2. I presume this is Thomas Fuller (1608-1661), chaplain to Charles II, and historian and anecdotalist.
3. Prodromos or forerunner.

Erasmus was one of the most brilliant scholars of any age, and enjoyed fine living. Both these would have been repressed by his being a priest, had he been lesser than Erasmus. But his brilliance shone through, he became a success at court and in the world of letters, and moved around Europe freely.

The nineteenth century historian J.A. Froude (from whom all the following direct quotations will be taken4) wrote that "He taught himself Greek when Greek was the language which, in the opinion of monks, only the devils spoke in the wrong place. His Latin was as polished as Cicero's".

In youth he was poor, his guardians having put him in the convent for his inheritance, and when he went to Paris and began to live a worldly life (letting his hair down, literally), his original support, by the Archbishop of Cambrai, was withdrawn. "Life in Paris was expensive, and Erasmus had for several years to struggle with poverty. We see him, however, for the most part--in his early letters--carrying a bold front to fortune; desponding one moment, and larking the next with a Paris grisette; making friends, enjoying good company, enjoying especially good wine when he could get it; and, above all, satiating his literary hunger at the library of the university."

At the age of about 28 he was discovered by Lords Mountjoy and Grey, and taken to England, which he loved. English character, English hospitality, English manners, not English beer though, as we saw above, and particularly English women with their habit of kissing every time you met5. From this point money flowed in: he got pensions and livings, his writing was successful, and he bestrode the European stage like a colossus.

Froude says, "Everywhere, in his love of pleasure, in his habits of thought, in his sarcastic scepticism, you see the healthy, clever, well-disposed, tolerant, epicurean, intellectual man of the world."

Now I would be misquoting Froude if I didn't add that he later goes on to unfavourably contrast the epicurean Erasmus with the crabbed, ill-educated, intolerant Martin Luther; but I prefer to repeat that description as unqualified praise.

You might think that back then the Christian world was ruled by the Bible: that this was the only book they knew, and they had it dished out to them constantly. Well they didn't: the New Testament was an obscure Latin text as little known to the general public as the lost books of Tacitus, says Froude. The theologians quoted passages in their own works, and that was all that was generally known of it. What Erasmus did was to go to the Greek, publish it (a criminally dangerous, almost heretical act in itself), translate and paraphrase it (into Latin so it could be widely understood), and interpret it.

He was also one of those responsible for restoring and disseminating the correct pronunciation of Latin and Greek. Both had changed a lot over the millennia, and Latin of course had turned into French and Italian and Spanish, and people pronounced it like their own language. Greek was known from native Greek-speakers, especially after the fall of Constantinople in 1453. Erasmus studied the ancient authorities and determined, more or less correctly, what the ancient tongues sounded like. This reform was adopted by English universities first, then spread. (English subsequently changed a lot in the Great Vowel Shift, so another reform was needed in the late nineteenth century to get back to the authentic values.)

He argued directly with Popes, and by letter. He was the centre of a reforming movement. If the real Reformation hadn't been happening at the same time in Germany, under Luther, and with battles and violent controversies, we might have had a slow Erasmian conversion of the mediaeval Church into a modern one, abandoning dogmas, allowing a broad and tolerant Church with no schisms or heresies, where good works and purity of heart were the requirements for entering Heaven, not scholastic formulae and venial indulgences. He argued this forcibly before the great prelates and lords of Europe.

Pity he never got the hang of the beer.

Notes.
4. Times of Erasmus and Luther, lectures delivered at Newcastle in 1867.
5. "English ladies," he said, "are divinely pretty, and too good-natured. They have an excellent custom among them, that wherever you go the girls kiss you. They kiss you when you come, they kiss you when you go, they kiss you at intervening opportunities, and their lips are soft, warm, and delicious."