What were the effects of crusade …

The Crusades had a bitter impact on the Muslim-Christian relations. The horrors of wars forced the Muslims to constrain all ties with the Christians. The need to protect the areas inhabited by mixed populations compelled the Muslims to further act more strictly with the Christians.
Apart from violence and terror, the Crusades had some positive impacts too. The Crusades gave a huge boost to commerce. The long-drawn-out wars created a constant need for the transportation of men and goods from the East to the West and vice versa. Goods from Damascus, Alexandria and Cairo flowed into the sea ports of Italy to be further shipped to Europe. The trading activities helped in increasing the influence of the Italian mercantile class on international trade. Thus, we can say that the Crusades had diverse effects on both Asia and Europe.