There are several great works of art in this exhibition—chief among them a magnificent de Kooning and a great Twombly—but their relevance to Rubens is somewhat tenuous. The exhibition’s overly broad parameters for inclusion render it rather unfocused, and, with relatively few works by Rubens himself, it devotes a majority of its space to his titular “legacy.” It is hardly a mystery that artists learn from, and are inspired by, the work of other artists, particularly when that artist is among the most influential painters of all time. Indeed, it is virtually impossible to think of any two significant figures in the history of art between whom some connection could not be drawn. The combination of canonical greats with contemporary pretenders can draw attention to a specific aspect of an artist’s work that might otherwise have escaped attention. Here, for all of the excellence of the works on show, it is merely window-dressing.