The primary cause of the Great Schism within Christianity, which occurred in 1054, was a combination of theological disagreements and political disputes between the Roman Catholic Church and the Eastern Orthodox Church. Key issues included the authority of the Pope, the role of the Holy Spirit in the Trinity, and practices like the use of leavened versus unleavened bread in the Eucharist. Political tensions were exacerbated by the growing divide between the cultures and languages of the Western Latin Church and the Eastern Greek Church. This schism led to a lasting division that has influenced Christian theology and practice throughout history.