Rendered with swift agile line, this sketch depicts two of the plateaux of Luxembourg: the Grünewald and the Rocher du Bock, with the northern stretch of the narrow Alzette valley below. Towards the centre, the castle of the Bock is visible followed by the two-storey arched Pont du Château and the Ville Haute with the Church of St Michael. Towards the foreground at right Turner has suggested some of the architecture of the French military engineer Vauban’s fortified towers. This sketch and those on folios 64 verso to 67 recto (Tate D28282–D28287; Turner Bequest CCLXXXVIII 64a–67) formed the basis of a gouache and watercolour drawing taken on blue paper in around 1839.1
Andrew Wilton, J.M.W. Turner: His Life and Work, Fribourg 1979, p.421 no.1022.