Karl Rahner's parents, Karl and Luise (Trescher) Rahner, had seven children, of whom Karl was the fourth. His father was a professor in a local college and his mother had a profound religious personality, which influenced the home atmosphere. Karl attended primary and secondary school in Freiburg, entering the Society of Jesus upon graduation; he began his Jesuit formation in the North German Province of the Jesuits in 1922, four years after his older brother Hugo entered the same order. Deeply affected by the spirituality of Ignatius of Loyola during the initial phase of his formation (1922–24), he concentrated the next phase of his formation (1924–7) on Catholic scholastic philosophy and the modern German philosophers: he seems to have been particularly interested in Immanuel Kant and two contemporary Thomists, the Belgian Jesuit Joseph Maréchal and the French Jesuit Pierre Rousselot, who were to influence Rahner's understanding of Thomas Aquinas in his later writings.