Koranic law protected Christians on condition of tribute and humbling

Evidence

In accordance with the teaching of the Koran they were given protection on condition of paying tribute. They had their own bishops, priests, churches, and monasteries, and many of their number were in responsible positions in the service of the Emirs of Cordova. So far, so good. But it was also laid down in the Koran that the Christians, though tolerated and protected, should nevertheless be “brought low.” In effect this meant no publicity of worship, no ringing of bells, no processions, and of course no blaspheming of the Prophet or Book of Islam. — R. W. Southern, Western Views of Islam in the Middle…, 115