Chopin's output as a composer throughout this period declined in quantity year by year. Whereas in 1841 he had written a dozen works, only six were written in 1842 and six shorter pieces in 1843. In 1844 he wrote only the Op. 58 sonata. 1845 saw the completion of three mazurkas (Op. 59). Although these works were more refined than many of his earlier compositions, Zamoyski opines that "his powers of concentration were failing and his inspiration was beset by anguish, both emotional and intellectual."