Estimates of crusade deaths range from as low as 1 million people all the way to 9 million. Because medieval societies did not always keep accurate birth and death records, it is impossible to know the exact number. Most scholars agree, however, that the total was somewhere in the millions.
The crusades began in the late 11th century and lasted into the late 14th century. They were intended as a way to cleanse the church and prepare for the second coming of Christ. Aside from attempted genocide because it was believed that all Jewish people needed to either be converted or dead before Jesus, many people also died in battle. Many Muslims were also killed when the Christian crusaders realized the vast riches they had accumulated and pillaged their cities and villages.