His teaching (the teacher of the German language and literature in the three upper classes) gave me much to do. For he covered in the fifth class the Greek and Latin poets, from whom selections were used in German translation. Then for the first time I began to regret once in a while that my father had put me in the Realschule instead of the Gymnasium. For I felt how little of the character of Greek and Roman art I should get hold of through the translations. So I bought Greek and Latin text-books, and carried along secretly by the side of the Realschule course also a private Gymnasium course of instruction. This required much time; but it also laid the foundation by means of which I met, although in unusual fashion yet quite according to the rules, the Gymnasium requirements. I had to give many hours of tutoring, especially when I was in the Technische Hochschule in Vienna. I soon had a Gymnasium pupil to tutor. Circumstances of which I shall speak later brought it about that I had to help this pupil by means of tutoring through almost the whole Gymnasium course. I taught him Latin and Greek, so that in teaching him I had to go through every detail of the Gymnasium course with him.
Source: Rudolf Steiner – GA 28 – The Story of My Life: Chapter II