How did Christians view other religions in the middle ages?

Answer 1

The Christian Church did not teach other religions in the Middle Ages. It banned them and persecuted their followers. Even to be suspected of something like witchcraft meant death by drowning or burning at the stake.

Answer 2

Everyone was Catholic in the middle ages, except for Jewish and Muslim. Both were not considered valid and were often discriminated against through out the time.

Answer

There was a lot more variation in this than one might imagine. We remember that Christians threw the Muslims out of Spain and threw the Jews out of various European countries. What we do not remember quite so easily is that people of all three religions existed peacefully, side by side, in Spain for much of the time between the Islamic conquest of Spain and the Christian reconquest. There were wars between states controlled by people of the two religions, but there were also wars between Christan states and wars between states controlled by Muslims. In fact, El Cid, who is regarded as a great Christian fighter against Islam, was in the hire of Muslim kings from time to time.

The relationship between Christians and Jews was just as varied. Christian kings invited Jewish people into their lands to benefit from the things those people would bring with them, including not only banking, but also knowledge of medicine and other science and mathematics. Descendants of those same kings, tired of being in debt (and not only to Jews), realized they could simply cancel the debts and get public backing in throwing the Jews out by blaming the Jews for some imagined wrongdoing.

Christians evangelized pagans, and when they got tired of doing that, they made war with them in a series of crusades in northern and eastern Europe.