Complex sentence: He did not, however, receive an extensive education, but only some private lessons and a few classes at the Gymnasium, he was compelled at the age of fifteen to enter the chancery of the Republic of Berne.
Split into simpler sentences: He did not, however, receive an extensive education, but only some private lessons and a few classes at the Gymnasium. He was compelled at the age of fifteen to enter the chancery of the Republic of Berne.