Rembrandt never went abroad, but was considerably influenced by the work of the Italian masters and Netherlandish artists who had studied in Italy, such as Pieter Lastman, the Utrecht Caravaggists, the Flemish Baroque and Peter Paul Rubens. After achieving youthful success as a portrait painter, Rembrandt's later years were marked by personal tragedy and financial hardships. Yet his etchings and paintings were popular during his lifetime, his reputation as an artist remained high and he taught many important Dutch painters for twenty years. Nevertheless, he suffered considerable financial problems at times, went bankrupt in 1656 and died in poverty. Rembrandt's portraits of his contemporaries, self-portraits and illustrations of scenes from the Bible are considered his greatest creative triumphs. His self-portraits form a unique and intimate autobiography in which the artist portrays himself without vanity and with utmost sincerity. Rembrandt's most important contribution in the history of printmaking was the transformation of the etching process from a relatively new reproduction technique into a true art form, together with Jacques Callot. His reputation as the greatest etcher in the history of the medium was established during his lifetime and has never been 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.