I believe it's quadratic, as quadratic matches the second time while linear matches the first time you find the differences.
One of the many effects of the Crusades was that the pope and the kings of Western Europe became and Europeans started to trade with the Middle East. Trade increased as they Western Europeans began to buy products such as sugar, lemons and spices which led to the increasing of trade and cultural diffusion
By 640, they had brought all of Mesopotamia, Syria and Palestine under the control of the Rashidun Caliphate
I believe 1 million jew were killed....
