Why was this speech so significant in changing history?

Why was this speech so significant in changing history? Paper details: Read and/or watch the following and make sure to comment directly on the primary source (original historical source document): Medieval Sourcebook: Urban II (1088-1099): Speech at Council of Clermont, 1095, Five versions of the Speech URLlink:http://www.fordham.edu/halsall/source/urban2-5vers.html Answer the following question: Why was this speech so significant in changing history?