The French painter Claude Lorrain (born Claude Gellée and often referred to simply as Claude) became the leading landscape painter in Italy during his lifetime. He began his career in Rome, where he trained under Agostino Tassi, who contributed to his interest in perspective. Known for his poetic use of light, Claude painted elegantly composed landscapes in the glow of dawn or early evening, layering semi-transparent oil paint onto his canvas. One of his favourite compositions, which he pioneered, was the idealized harbour scene, flanked by palaces and classical ruins and with luminous light effects reflected on the water’s surface. In 1635 he began the Book of Truth, documenting sales and patrons so as to safeguard against the forgery of his work; containing 200 etchings of Claude’s paintings, the book became an important work of art in its own right.