Rembrandt's portraits of his contemporaries, self-portraits and illustrations of scenes from the Bible are regarded as his greatest creative triumphs. His self-portraits form a unique and intimate autobiography, in which the artist surveyed himself without vanity and with the utmost sincerity. Rembrandt's foremost contribution in the history of printmaking was his transformation of the etching process from a relatively new reproductive technique into a true art form, along with Jacques Callot. His reputation as the greatest etcher in the history of the medium was established in his lifetime and never questioned since. Few of his paintings left the Dutch Republic while he lived, but his prints were circulated throughout Europe, and his wider reputation was initially based on them alone.