String Quartet No. 19 in C major, K.465 "Dissonance"

The quartet opens with an introduction, marked Adagio, that first-time listeners often find unsettling: the four instruments enter one by one on notes that clash against each other, creating a foggy, unresolved sound before the music settles into a bright C major Allegro. This slow opening lasts only about a minute and a half, but it gives the whole quartet its nickname. Once the Allegro begins, the mood turns cheerful and conversational, with the four players trading a simple, energetic tune back and forth.

The second movement, an Andante cantabile, is lyrical and warm, built around a singing melody that moves between the instruments like a shared conversation. Listen for moments where the accompaniment turns restless underneath the melody, adding a touch of tension to the otherwise calm surface.

The third movement is a Menuetto, a stately dance in triple time with a contrasting middle section, or trio, that briefly shifts to a darker color before the dance returns.

The finale is a fast, good-humored Allegro molto in the style of a rondo, full of quick exchanges between the instruments. The dissonant fog of the opening is long forgotten by this point, and the quartet ends with clear, confident energy.

Mozart composed this quartet in Vienna in January 1785, the last of a set of six string quartets he wrote between 1782 and 1785 as a tribute to Joseph Haydn, whose own quartets had inspired him. The set became known as the "Haydn Quartets," and Mozart dedicated them to Haydn in a published edition later that year. This particular quartet earned the nickname "Dissonance" because of its unusual slow introduction, whose clashing harmonies puzzled some early listeners and even led to rumors that the printed music contained errors. Haydn himself is said to have heard the six quartets performed and praised them highly to Mozart's father, Leopold. The "Dissonance" quartet has remained one of the most performed and discussed works in the string quartet repertoire, often singled out for how its strange opening resolves into clarity.