The Great Schism of 1054 was the division of the Christian church into two the Western (the Roman Catholic Church) and the Eastern (the Eastern Orthodox Church).
The breakup was the result of years of tensions arising from theological and political differences between them. For instance, The Catholic Church promoted using unleavened bread for the ceremony of communion and the Orthodox Church didn't, the Roman church held that the pope (the spiritual leader in Rome) had authority over the patriarchs, religious leaders in the east, and Eastern church disagreed, Westerns believed that Jesus was fully divine, whilst Easterns believed that he had two natures: human and divine.