The string quartet literature is notable for throwing super-complex challenges at the players; after all, this is the most cohesive medium for ensemble playing, and quartets play together for years or decades and can polish their communication and coordination skills to the highest degree. For that reason, composers have striven their utmost to present path-breaking difficulties and daring quartets to conquer them. One sub-history of 20th/21st century music has been the interplay between quartet composers and the groups performing their music. The avatar of all of this is late Beethoven, whose Große Fuge pushed the boundaries of playability in its day, and whose late quartets were composed with the skills of the Schuppanzigh Quartet in mind.