Studies of Mozart’s Concerto No. 20 in D Minor, K. 466, and especially of commentaries on Beethoven’s cadenza for its first movement prompt this analyst to investigate their claims, in preparation for her first performance of the concerto. Roughly twenty-four years span the interval between Mozart’s completion of  K. 466 in 1785 and Beethoven’s cadenzas for its first and last movements: it is now believed that he wrote all of his concerto cadenzas in 1809, thus well after he had published all but one of his own concerti. For Richard Kramer, it would be too simple to dismiss Beethoven’s outrageously Beethovenian (rather than echt Mozartean) K. 466 cadenzas “as an aberration foreign to the style”. Something more personal is at hand—an agenda, a confrontation, an assault; Beethoven overtly ‘violates’ his Mozartean legacy (Kramer 1991; 2008).
Hardly irrelevant to the question of Beethoven’s agenda is the measure of his engagement with Mozart’s text—its formal, motivic, and dramatic content; about this Kramer agrees. Might Beethoven have responded even more deeply to that text than has hitherto been recognized? His fingers and ears might easily have discovered the remarkable, even novel, motivic relations that Mozart’s opening solo idea generates not just within the first movement but also within the finale—relations that for Charles Rosen (1971; 1998) are “almost too obvious”. Broadening the context of Matthew Bribitzer-Stull’s 2006 voice-leading graph of the cadenza further suggests that Beethoven grasped what Heinrich Schenker, more than a century later, would call ‘the primary tone’, repeatedly prolonged by its upper neighbor. Beethoven’s ‘last word’ in the cadenza throws that tone and its neighbor into impassioned relief, and his overwhelming conclusion simply must be understood to achieve the movement’s essential structural close (ESC). Given such details, pianists who choose to play Beethoven’s cadenza might find new impetus for the challenge of performing ‘Beethoven’ and ‘Mozart’ in synergy within a single movement.