We can talk about Christian history in the sense of the historical development of the Christian faith but it's really impossible to make an accurate blanket statement like "Christians are violent" or "Christians aren't violent" etc, that's because with the exception of a few events or very early Christian history it is impossible to talk about "the Christians" as a group. Almost every European state was Christian, but their actions as states had more to do with political interests than their being Christian. Even when talking about the crusades it's impossible to say that the Christians did this or that because during the crusades Christians often fought against other Christians — for instance the Sacking of Constantinople where the (Latin/Western) Christian crusaders destroyed the (Greek/Eastern) Christian city of Constantinople. The reconquista of the Iberian peninsula is oftentimes portrayed as a straightforward campaign by Christians against Muslims, but in fact it was not uncommon for a Christian Lord to be a vassal of a Muslim ruler and fight against other Christians.

If you would like to ask about specific doctrines or specific historical events it would be easier to give you an answer. I am only knowledgeable on the very basics of Islam and most of my knowledge about Islamic history is in relation to the interactions of Muslims and Eastern Christians/the Byzantine Empire during the expansion of Islam, especially so unless your questions are in regards to that specifically I can't be of much help on Islam at all.

I echo what /u/Markos-Evgenikos said. It is extremely difficult to separate religious motivations for certain acts (like the Crusades, Ottoman Expansion into Europe, etc) from the political considerations behind them. Even things that seem relatively easy to ascribe to religion, like the development of Islamic law in the first few centuries after Muhammad, often have political leanings behind them.

In the reverse of /u/Markos-Evgenikos, I can try shed some light on the Islamic side of things if you have a specific question, particularly in regards to early Islamic history, Islamic law, etc.

Edit: Spelling