Philip Sherrard, an Orthodox theologian, asserts that the underlying cause of the East-West schism was and continues to be "the clash of these two fundamentally irreconcilable ecclesiologies." Roger Haight characterizes the question of episcopal authority in the Church as "acute" with the "relative standings of Rome and Constantinople a recurrent source of tension." Haight characterizes the difference in ecclesiologies as "the contrast between a pope with universal jurisdiction and a combination of the patriarchal superstructure with an episcopal and synodal communion ecclesiology analogous to that found in Cyprian." However, Nicholas Afansiev has criticized both the Catholic and Orthodox churches for "subscribing to the universal ecclesiology of St. Cyprian of Carthage according to which only one true and universal church can exist."