Ludwig van Beethoven's late string quartets are:
These six works are Beethoven's last major completed compositions. Extremely complex and largely misunderstood by musicians and audiences of Beethoven's day, the late quartets are now widely considered to be among the greatest musical compositions of all time,[1][2][3] and have inspired many later composers.
The five Late Quartets, written in the final years of [Beethoven's] life, transcend anything he or anyone else had ever composed.
...generations of listeners have hailed [his late string quartets] as a pinnacle of Western civilization...