Ludwig van Beethoven's Piano Sonata No. 8 in C Minor, op. 13 was titled "Pathètique" by the composer himself, unlike most of the other "named" sonatas. It was published in 1799 (though written the year before), and dedicated to Beethoven's friend Prince Lichnowsky[?].

It has become a particularly famous piece, despite being difficult to play. It is noteworthy as an early example of several elements which came to define music of the romantic period, such as deep harmonic developments, and composers taking increasing liberties with sonata (and other) classical forms. Musical historians generally agree that Beethoven was the first romantic composer, and some even go so far as to regard this sonata as defining the start of the romantic period.

The sonata is in three movements:

1. Grave; allegro di molto e con brio
2. Adagio cantabile
3. Rondo: allegro

The first movement is in standard first movement sonata form, though it is characterised by the long grave introduction, which delays the primary theme until the exposition at the start of the allegro section. The movement is in 4/4 time in the key of C minor, modulating to the relative Eb major.

The adagio movement opens with the famous and beautiful cantabile ("in a singing style") melody. It is generally considered a rondo form, because of the repetition of this Ab major theme, though rondos are somewhat unusual for the slow second movements in sonatas.

The sonata closes with a 2/2 sonata rondo movement in C minor, which departs to Eb and Ab major and refers to themes from both of the previous movements. Interestingly, notes of Beethoven's show that he originally considered the movement as a rondo for piano accompanied by another instrument — perhaps a violin.