I need help please: To compare and contrast Roman Catholicism with Eastern Orthodoxy ?

As I understand it, what originally caused the Eastern Orthodox bishops to break with Rome was a disagreement. The Bishop of Rome ---or the Pope, as we now know him--- held that he was supreme among ALL the bishops. The Eastern bishops held that the Bishop of Rome was first among equals. Eastern Orthodox churches tend to be more nationalistic in character than the Roman Catholic church. Also, they use different calendars. Nations influenced by the Catholic church use what is known as the Gregorian calendar (named after Pope Gregory XIII). The Eastern Orthodox churches continue to use the Julian calendar (named after Julius Caesar). There is a 12-day difference between these 2 calendars.