The Christians in medieval western Europe with reading access to the Quran were mostly scholars, and their scholarship was always tinged (or more than tinged) with Islamophobia. But the translators took great care with their texts, and some of its uses in the Latin west will surprise you.

The Quran in Latin, for which I'll use the generic term Liber Alkoran here, was reasonably popular in the Middle Ages. Robert of Ketton's 1143 translation for Peter the Venerable, Lex Mahumet pseudoprophete, survives in about 25 manuscripts. The others, by Mark of Toledo, Flavius Mithridates, and Iohannes Gabriel Terrolensis for Egidio da Viterbo, give us a combined 15 manuscripts. Robert's also went through two 16th century print editions, which would be about 500 copies each.

As far as vernacular goes--there are some surviving manuscripts in Castilian Spanish from the late Middle Ages, although to my knowledge those circulated in Muslim communities.

The first major use of Liber Alkoran was a source for polemic authors.

Robert's translation, the most popular, was actually part of a compilation of translations from Arabic (Islamic and Christian texts alike) compiled by Peter the Venerable, a famous abbot and sometime counterpart/opponent of Bernard of Clairvaux. Robert sets it out explicitly in his introduction that his translation should be a source to argue against the lex letifera ("death-dealing religion").

The scribes of Lex Mahumet took up the charge, supplying Robert's text with an extensive framework of marginalia that offer color commentary of a sort: "this is the stupidest" "lying" "enveloped in absurd lies and the characteristic repetition of incantations." I've talked earlier on AH (way earlier, lol) about how the glossers shape Islam into a violent religion through their comments.

Mark of Toledo's translation usually circulated with a similar polemic framework, as did da Viterbo's. (Da Viterbo gets the credit instead of Terrolensis because we know nothing about the latter). However, a couple of manuscripts of his and then that of Mithridates actually lack a polemical gloss.

The lack of Islamophobic marginalia on those mss is especially significant because a consistent pattern across the translations is: the translations themselves are meant to be accurate.

In fact, Robert, Mark, and Terrolensis actually put in a lot of effort to use Muslim Quranic commentaries to guide them through thorny translation difficulties! They were trying not to distort the actual teachings, even where doing so might serve Christian polemical purposes by making Islam look bad.

And that gets to the second use of the Quran: scholarship. Even in its glossed form, the presentation of Robert's translation actually mirrors 12th-14th century scholastic mss. With colored initials and a system of paragraph divisions, the text would look like any other text studied by scholars at university or in a monastic/cathedral school.

Furthermore, Robert actually blends information from the commentaries into the body text of his translation--this is not unusual for biblical-derivative texts in the later Middle Ages!

Medieval Christian scholars handled Liber Alkoran like they would the study of a Christian text, even if their view of Islam was diametrically opposite and their ends were (or claimed to be) polemical.

But after polemic and scholarship, a third use of Liber Alkoran was prestige. Yup, Mithridates' ("so defective as to be virtually useless," says Tom Burman) translation survives as a luxury book. Complete with gold leaf on the frontispiece and personalized to the wealthy patron who commissioned it. False holy book it might be, but to own it made the patron look rich, educated, and tapping into that lure of the exotic.

However, all of this is basically an introduction to my favorite use of Liber Alkoran in the Middle Ages: as a source for Christian preaching. And no, I'm not kidding.

See, in the 14th and 15th centuries, one of the biggest intra-Christendom debates was the Immaculate Conception: the belief that Mary, mother of Jesus, was herself conceived without the stain of original sin. It was the official teaching of the Franciscan (preaching) order; it was a wildly popular belief among regular Christians.

But the Dominicans had a Thomas Aquinas Problem.

The Franciscans' sibling/rival order, also preachers (literally: O.P. is Ordo Predicatorum), were so much more beholden to their "second founder," Thomas, than the Franciscans were to their alter Franciscus Bonaventure. This mattered because, in the 13th century when the two of them were doing theology, the Immaculate Conception was NOT in vogue as belief. So both of them explicitly denied it.

The Franciscans shrugged and said, "Whatever." The Dominicans dug in their heels and said, "But Thomas."

What has this to do with the Quran?

Well, actually nothing.

But it does have to do with a hadith. Specifically, one that says:

that Mary and her child were born neither in original sin nor with affliction...and that she bore her child through the Holy Spirit

...as Marquard von Lindau, one of the most popular vernacular authors in 15th century Germany, has it.

But he has no idea it's from a hadith and not the Quran. Given the mishmash of Robert's translation with commentaries, and the other texts circulating in the anthology, it's a completely understandable conflation:

and says, as the Saracens wrote in the Quran

But you'll notice one final thing here. Yes, Marquard (and plenty of others--this also shows up in the wildly popular sermon collection Dormi secure) is citing "the Quran" in support of what he wants to be official Christian dogma. But in assigning authorship of the Quran to Muhammad and Muslims, he is also directly contradicting Islamic dogma of the Quran as divine revelation.

We don't know that much about Marquard, so I can't tell you whether he, specifically, was doing it on purpose or whether he was just following earlier Christian writers who did it on purpose.

But one way or the other, to all appearances, Christian preachers in the late Middle Ages were teaching Christian doctrine to Christian lay people with the explicit aid of the Quran.

Short answer:

[restricted to Latin Christendom-- Eastern Christianity would be different]

Scholarly, theological and diplomatic interest pretty exclusively-- almost no popular religious interest; indeed, in the middle ages most ordinary folk couldn't speak Latin or read the Bible (which was almost exclusively in Latin). To the extent that the Qur'an was as a religious text, it was principally to identify its errors, or to identify places where it supported scripture, or to facilitate conversion of Muslims.

Discussion:

There was popular interest in aspects of the lives of Muslims -- particularly the more lurid topics-- but not in the religion per se. Remember that before the Reformation, ordinary Christians themselves were often illiterate, and were not necessarily Bible readers-- they got their religion in Church, rather from the Bible itself. Before printing, books were scarce, ordinary folks didn't have Bibles, much less Qur'ans.

Of material translated from Arabic, the Qur'an itself was just one part of Europe's "opposition research" on a then fearsome enemy. One typical comment gives you a flavor of these works

'It is to be known', wrote Riccoldo da Monte di Croce in his Contra legem sarracenorum, one of the most widely read Latin-Christian tracts against Islam in the Middle Ages, 'that the Devil vomited forth in Muhammad the refuse of all the ancient heretics'. The Qur'an, he insisted, is 'not the religion [lex] of God, for neither the Old Testament nor the Gospel bears witness to it', and, whatever be its stylistic value, 'it is obvious that the Qur'an is not the religion of God because it does not concur in meaning with the religion of God [as revealed in the Bible]

Europe understood Islam as a military threat, and the title of the first translation, by Robert of Ketton, Lex Mahumet Pseudoprophete gives you a pretty good idea of how the Qu'ran was seen. Robert was famously encouraged to translate the Qur'an by Peter the Venerable, so as to know better how to convert Muslims.

Note that Robert of Ketton translated several other documents from Arabic (he was in Spain), including al-Kindi's Astrological Judgements, and a history of the early Caliphate whose title tells you what his point of view was Chronica mendosa Saracenorum ("Lying chronicles of the Saracens")

[S]cholarly and antiquarian interest in the Qur'an was never divested from the context that brought it into being. Robert's translation was intended to be circulated with other translations from Arabic, including the scathing letter of 'Abd al-Maslh al-Kind1, that showed Islam in the worst possible light. And later readers of copies of Robert's and other translations (one of whom may have been William Tyndale) were accustomed to add notes in the margins that made abundantly clear their concerns and opinions about Islam. As might be expected, Christians generally concentrated on verses about their own beliefs and typically commented condescendingly about them. And in other places they wrote some times with peppery terseness about the errors they detected in the teachings they read.

Thomas E. Burman of the Medieval Institute at Notre Dame University has made a specialty of examining reading the Qur'an -- both in the original Arabic and in translation-- in medieval Europe. He's got remarkable examples from marginalia written by medieval monks, giving evidence of "what they were thinking as they read this", for example

MS Arabe 384 contains a lengthy note - squeezed on to one of the folios that contain the errors of the Qur'an drawn up by the earlier reader - which is probably an initial sketch of the ninth chapter of Contra legem Saracenorum. This note begins with the words "This book [i.e., the Qur'an] is against the holy apostles because it says that they were Muslims and imitators of Muhammad," and goes on to list how it also inveighs against the Gospel writers, holy prophets, patriarchs, the Blessed Virgin, the Son of God, the Holy Spirit, God the Father, God in general (simpliciter), and, in addition, speaks untruths about demons, each of these assertions defended briefly by evidence from the Qur'an, often cited by sura number and folio of the manuscript itself.

​

sources:

Tafsīr and Translation: Traditional Arabic Qurʾān Exegesis and the Latin Qurʾāns of Robert of Ketton and Mark of Toledo

Reading the Qur'ān in Latin Christendom, 1140-1560

How an Italian Friar Read His Arabic Qur'an

POLEMIC, PHILOLOGY, AND AMBIVALENCE: READING THE QUR5AN IN LATIN CHRISTENDOM

Peter the Venerable and Islam