By the end of the 1630s he was established as the leading landscapist in Italy, and enjoyed high prices for his work. These gradually became larger, but with fewer figures, more carefully painted, and produced at a lower rate.
He was not generally an innovator in landscape painting, except in introducing the sun into many paintings, which had been rare before. He is now thought of as a French painter, but was born in the independent Duchy of Lorraine, and almost all his painting was done in Italy; before the late 19th century he was regarded as a painter of the "Roman School". His patrons were also mostly Italian, but after his death he became very popular with English collectors, and the UK retains a high proportion of his works.