The catalogue of the Pantzer collection (No.46) says that this watercolour is a companion to the 'Lake of Thun' in the Taft Museum, Cincinnati, and gives I840 as the probable date; but the recently discovered watermark provides evidence that this is in fact one of the latest of all Turner's finished watercolours. It is even freer in handling than the group usually dated to about 1845, which includes 'Bellinzona' and 'Pallanza' (Nos.613, 615), and is in many ways close to some of the rough sketches of Swiss subjects which may have been made at this date. The subject was probably taken from material gathered during Turner's visit to Geneva in the summer of 1841, which occasioned a number of pencil sketches of the Lake in the 'Rhine, Flushing and Lausanne' sketchbook (T.B.CCCXXX) and watercolour views of the city in the 'Fribourg, Lausanne and Geneva' sketchbook (T.B.CCCXXXII); there is also a crudely-stitched folder of torn paper, T.B.CCCXLIV-27I to 289, which contains rough sketches apparently of Lake Geneva. However, no obvious source for the composition of the Pantzer watercolour is among these studies.