Symphony in Grey and Gold may date from between 1868 and 1878. 1

According to Lucas (Luke) Alexander Ionides (1837-1924), Whistler sold him 'A Symphony in grey and gold' in the early 1880s. 2 The title of 'Symphony' was more usual for a figure subject than for a landscape, and might indicate an earlier date, in the late 1860s. However, if it was a foggy or evening scene, it could date from the late 1860s or 1870s.

It is possible that it is Nocturne: Westminster - Grey and Gold [YMSM 144], which is also difficult to date.