After the defeat of Napoleon, Europe was again open to travel and in 1817 J. M. W. Turner visited the battlefield of Waterloo and then journeyed up the Rhine River. On his return to England, he produced a large number of watercolors based on graphite sketches he made of the Rhine. Fifty-one of these drawings, including this one, were acquired by Walter Fawkes of Farnley Hall, one of Turner’s most important patrons as well as a close friend. Although not made on the spot, this drawing preserves a freshness and spontaneity. Throughout his career, Turner adjusted his watercolor technique to the scenery he encountered, and as a result, each set of drawings possesses an individual style.
Source: Alan Chong, "The Roman Tower, Andernach," in Eye of the Beholder, edited by Alan Chong et al. (Boston: ISGM and Beacon Press, 2003): 191