There are a lot different answers to this question so what specific things are you looking for?
A. Urban II
These incursions prompted the emperor of Byzantium, Alexius I Comnenus to send a delegation to Piacenza, Italy, asking Pope Urban II in March 1095 for help against the Turks. On November 27, 1095, in Clermont, France, Pope Urban II called for a crusade to help the Byzantines and to free the city of Jerusalem.
The South was fighting a defensive war. The confederates prefer a defensive doctrine to defeat the numerically superior Union forces and to invite foreign powers especially Great Britain in their side thus winning the war against the Union forces in the American civil war.
usually if you look it up they will give you essays on it. which might be more helpful