Object lessons: best of London's Old Master auctions

Claude Gelle, called Claude Lorrain, A pastoral landscape with a shepherd and shepherdess beside their livestock in an Arcadian landscape with drovers on a bridge beyond (1635-37)
Bonhams, New Bond Street, Old Master Paintings, 6 July
Estimate 600,000-800,000Claude Lorrains lyrical observations of landscape, light and nature revolutionised painting in the 17th century. Before then, pure landscape had been looked down upon: it offered only aesthetic simplicity when compared with the moral superio