Claudio de Lorena

In the Rome of the mid-1600s, a painter from the duchy of Lorraine had become so sought-after that other men were faking his work to cash in. Claude Gellée, known simply as Claude Lorrain, painted luminous harbours and pastoral landscapes bathed in a soft rising or setting sun, and Europe's cardinals and aristocrats paid heavily for them.

His answer to the forgers was a book. From about 1635 he kept the Liber Veritatis, the Book of Truth, a bound album in which he drew a careful copy of nearly every finished painting as it left his studio, often noting the buyer's name and the date. It ran to some 200 drawings, and it let a genuine Claude be told from a fake.

He was really a painter of light more than of places. The mythological or biblical figures in his scenes are often small, tucked into a corner, while the eye travels back toward a hazy sun on the horizon. That effect fixed the European idea of the ideal landscape for close to two centuries, and the English painter Turner, more than a hundred years later, asked in his will to have two of his own canvases hung beside Claude's in London.