Orthodox theologians assert that the theological division of East and West culminated into a direct theological conflict known as the Hesychasm controversy during several councils at Constantinople between 1341 and 1351. They argue that this controversy highlighted the sharp contrast between what is embraced by the Catholic Church as proper (or orthodox) theological dogma and how theology is validated and what is considered valid theology by the Eastern Orthodox. The essence of the disagreement is that in the East a person cannot be a true theologian or teach the knowledge of God, without having experienced God, as is defined as the vision of God ("theoria"). At the heart of the issue was the teaching of the Essence-Energies distinctions (which states that while creation can never know God's uncreated essence, it can know his uncreated energies) by Gregory Palamas.