I found this on George Grant's blog about Islam - it was Luther and Calvin's thoughts about Islam nearly 500 years ago:
Luther and Calvin on Islam
John Calvin in a sermon on Deuteronomy 18:15 maintained that Muhammad was one of “the two horns of antichrist.” In his commentaries on Daniel (7: 7-18), Calvin put forward the theory that the Muslim Turks were the little horn that sprang up from the beast. As the Turks had conquered much of the old Roman Empire, much of the prophecies concerning Rome could apply to the Muslim world. He believed that Islam was one of the two legs of the later Roman Empire described in Daniel 2. In expounding Daniel 9, Martin Luther noted that among others, the prophet Daniel was talking about the Muslim Turks, who at the time were invading Europe, “In the latter part of their reign, when rebels have become completely wicked, a stern-faced king, a master of intrigue will arise. He will become very strong, but not by his own power. He will cause astounding devastation... He will cause deceit to prosper and he will consider himself superior. When they feel secure, he will destroy many and take his stand against the Prince of princes. Yet he will be destroyed, but not by human power.” Of Daniel 9: 23-25, Luther wrote that the “two regimes, that of the Pope and that of the Turk, are... antichrist.” Commenting on Daniel 11:37, Calvin wrote that Muhammad “allowed to men the brutal liberty of chastising their wives and thus he corrupted that conjugal love and fidelity which binds the husband to the wife... Mohammad allowed full scope to various lusts--by permitting a man to have a number of wives... Mohammad invented a new form of false religion.”Luther noted that Christ warned about false prophets coming from the desert (Matthew 24: 24-26) and this certainly included Muhammad. Commenting on 2 Thessalonians 2: 3-12, Calvin wrote, “the sect of Mohammad was like a raging overflow, which in its violence tore away about half of the church.” In his commentary on 1 John 2: 18-23, Calvin states that the Turks “have a mere idol in place of God.” In a sermon on 2 Timothy 1:3, Calvin explained, ”The Turks at this day, can allege and say for themselves: ‘We serve God from our ancestors!’ ... It is a good while ago since Mahomet gave them the cup of his devilish dreams to drink, and they got drunk with them. It is about a thousand years since those cursed hellhounds were made drunk with their follies... Let us be wise and discreet! For otherwise, we shall be like the Turks and Heathen!” Luther observed from 1 John 2: 18-22 and 4: 1-3, “Who is the liar? It is the man who denies that Jesus is the Christ. Such a man is the antichrist--he denies the Father and the Son.” Of 1 John 2: 22 he wrote that Muslims “deny both the Fatherhood of God and the Deity of Christ--hence they are liars. They testify against the truth of God’s Word.” On 1 John 4: 3-6, he wrote “but every spirit that does not acknowledge Jesus, is not from God. This is the spirit of the antichrist... this is how we recognize the spirit of truth and the spirit of falsehood.” He observed that the Muslims ultimately want “to eradicate the Christians.” Not much ambivalence there--not that Luther or Calvin were ever really ambivalent about anything!