The second half of the eighteenth century saw the emergence of Western classical music’s most perfect form – the string quartet. And the quartets written first by Haydn, then by Mozart, then by Beethoven had a concentrated sophistication which was never remotely reached by their symphonies. Mozart’s six “Haydn” quartets are among the miracles of the genre, and the inscription penned above them was touching: speaking of them as his progeny, and acknowledging his huge creative debt, Mozart dedicated them to Haydn as his “dearest friend” who would “look indulgently on their defects” – though no critic would dare point to even one such thing in these intricate masterpieces.