Johann Sebastian Bach's parents both died before he was ten, and he moved in with his eldest brother Johann Christoph, who raised him from that point on. According to J.S. Bach's obituary written by Carl Philipp Emanuel Bach and Johann Friedrich Agricola, it was under Christoph's guidance that J.S. Bach "laid the foundations of his keyboard technique". Christoph is however more commonly remembered for denying his younger brother access to a book of his keyboard pieces:
The book was kept in a cupboard secured only by lattice doors. He [Sebastian] was therefore able to reach through the lattice with his small hands and roll up the book, which had only a paper cover; in this way he was able to remove it at night, while everyone else was in bed, and to copy it by moonlight, since he had no other light. After six months he was delighted to have this musical treasure in his hands, and tried secretly and with unusual zeal to profit from it until, to his deep dismay, his brother got to know of it and was harsh enough to confiscate the music he had taken such pains to copy.