5 seconds of Googling reveals:
>On July 4, 1187, the Muslim forces of Saladin (Salah al-Din) decisively defeated the crusader army south of the Horns of Hattin in Palestine, capturing Guy, king of Jerusalem; Reginald of Châtillon, Saladin’s enemy whom he personally killed; over two hundred Knights Hospitaller and Templar Knightly Orders whom he ordered to be killed; and many crusaders whom he ransomed. The remaining captured Christians were sold on the local slave markets. [1]
Such a friendly guy, that Saladin!
Your attempt to draw some great moral distinction between evil Christian and good Muslims is massively confused and, given its underlying intent to delegitimize certain religious/ethnic groups today, actually nauseating.
The reality is that pretty much everyone involved in the Muslim conquests, the Crusades, the Muslim re-conquests, and all conflicts of that era were absolutely brutal. Mohammed himself ordered and carried out countless torture sessions, battles, and massacres, of soldiers and civilians. So as did the Romans and the Franks and everyone else.
If they were ever merciful, on any occasion, it was not for moral reasons, but strategic/political ones.
The ancient world is brutal. Stop trying to manipulate stories from it to stir up hate towards peoples' identities today. We have enough things to fight about already.
[1] http://www.history.com/topics/saladin