For many, the word persecution has become almost synonymous with the experience of Christians suffering for their faith in Muslim lands. Just last year, several cases reached the attention of the public, including those of Christian publishers Necati Aydin, Ugur Yuksel, and Tilmann Geske, who suffered brutal deaths at the hands of Muslim Turks. Months later, Rami Ayyad, a Palestinian who managed a Christian bookstore in Gaza received death threats from Muslims angry with his ministry and was later found dead. A recent article in the Wall Street Journal pointed out the growing international problem of radical Muslim attempts to ban and severely punish any criticism of Muhammad or Islam, even in Western lands.

If Muslims forbid Christians (or anyone else) to criticize their religion, is this persecution? How should Christians respond? Long before our modern debates about how Muslims and Christians can coexist peacefully, the church in medieval Cordoba, the capital of Islamic Spain, wrestled with some of the same questions.

In the 700s, a small Muslim army from North Africa launched a successful conquest of Spain and set up the first Islamic state in Europe. Under Muslim rule, "al-Andalus" (which endured from 711 to 1492) flourished economically and culturally. Cordoba, the capital, boasted a population ranging from 250,000 to 500,000 (compared to 15,000 in London). Many scholars attribute the grandeur of Cordoba to the creative mixing of Muslims, Christians, and Jews. These scholars portray Islamic Spain as a model of tolerance, where Muslim rulers "protected" their Christian subjects and gave them a remarkable amount of religious freedom.

But a series of events in the ninth century throws some doubt on this assertion. In 850, Muslim acquaintances of a Cordoban priest named Perfectus asked him what he thought of Christ and Muhammad. Perfectus affirmed his belief in Christ's divinity, but he refused to say anything about Muhammad unless they swore their friendship. They agreed. Perfectus then accused Muhammad of teaching false doctrine, committing adultery with his cousin Zaynab, and having been seduced by demons. Angered by what they heard, his Muslim "friends" made Perfectus's "blasphemy" public in the streets.

A string of martyrdoms followed. By the time the priest Eulogius was executed in 859, a total of 48 Christians had been put to death for defaming Muhammad's name. But Perfectus' story is atypical of the martyrs. More characteristic is that of the second martyr Isaac, who entered the court and pretended to wish to convert to Islam, but then used the opportunity to call Muhammad a liar, accuse him of having been filled with the devil, and claim that his followers could expect eternal punishment.

Church authorities sharply criticized Isaac and others like him for their actions. Paul Alvarus, a close friend of Eulogius, wrote that Reccafred, the archbishop of Seville, "descended upon churches and clergy like a violent whirlwind, and threw as many priests as he could into jail." While we don't know exactly what Reccafred thought (since only Alvarus and Eulogius wrote about the martyrdoms), he and other leaders probably deemed the marytrs' movement a poor imitation of early martyrs who had died under Roman persecution. Members of the early church had been hunted down, arrested, and executed just for being Christians, or for refusing to participate in worshiping Roman gods. Muslims, however, claimed to believe in God—they did not kill Christians for simply being Christian. As these church officials saw it, the martyrdoms only made life difficult for the Christians of Cordoba, and did nothing to help the cause of the church there.

But Eulogius countered that Muslims did not believe in God because they rejected Christ's claim to divinity, and that they were indeed persecuting Christians. Alvarus argued, "What could be a greater persecution, what more severe kind of degradation is to be feared than when a person cannot say in public what he believes by reason in his heart?" What good was it to say Christians were "protected" if they could not criticize Islam publicly? Were Christians not obligated to resist this form of persecution and proclaim the truth as they believed it? This was the position of the martyrs.

Just as the Christians of Cordoba wrestled with how to respond to Islamic power and the limitations Islam placed on them, so must we consider what it is that we should be about as Christians when faced with a resurgent Islam. Does our faith compel us to be publicly critical of Islam? If we are attacked for such criticism, is that indeed persecution? Does criticizing Islam advance the kingdom of Christ, or are we needlessly putting fellow believers at risk? The blood of the Cordoban martyrs—and many other Christians who have died for attacking Islam—continues to cry out for answers to these questions.

Steven Gertz is a graduate student in Islamic studies at Oxford University and a CHRISTIAN HISTORY editorial adviser.