text: Between the Eastern Orthodox and the Roman Catholics??\n\nIsn't one of the main differences that most Roman Catholic priests are not married and most Eastern Orthodox priests are permitted to marry?  -- I think that "would affect family life".\n\nAnother difference ... Roman Catholics acknowledge the supremacy of the Roman Pontiff; Eastern Orthodox do not.\n\nSimilarities include, I think, that they all believe in transubstantiation.