Григорий Палама
The Eastern Orthodox theology of the Jesus Prayer enunciated in the 14th century by Gregory Palamas was generally rejected by Latin Church theologians until the 20th century. Pope John Paul II called Gregory Palamas a saint, a great writer, and an authority on theology. He also spoke with appreciation of hesychasm as "that deep union of grace which Eastern theology likes to describe with the particularly powerful term 'theosis', 'divinization'", and likened the meditative quality of the Jesus Prayer to that of the Catholic Rosary.