The collection was published as the Liber Veritatis ('Book of Truth'), although this term is also used for the original. Claude kept the sketchbook from around 1635, as he first began to achieve success, until his death in 1682. It recorded almost every painting he produced, with notes on the subject, patron, and date. Claude told his biographer Filippo Baldinucci that he kept the record as a defence against other painters passing their work off as his.
Nevertheless, this collection of sketches and notes has proved a vital resource for scholars and is regarded as a work of art in its own right. Earlom's copies use etching with mezzotint to replicate Claude's pen-and-ink wash drawings, and were published between 1774 and 1777. Although now in the collection of the British Museum, the original remained in the possession of the Dukes of Devonshire until 1957. The publication of these prints therefore made the work accessible to artists and the general public. The prints were a huge success; they were recommended by drawing teachers as models for copying, and had a significant influence on English landscape artists of the time.
