What event increased the tension between the east and the west in 800 ad?

In 800 AD, the crowning of Charlemagne as Emperor by Pope Leo III in Rome significantly increased tensions between the Eastern and Western Christian realms. This event symbolized a rival claim to authority over Christendom, challenging the Byzantine Empire's influence in the East, where the Byzantine Emperor considered himself the rightful Roman Emperor. The act deepened the schism between the Eastern Orthodox Church and the Roman Catholic Church, setting the stage for future conflicts and divisions.