Chopin has figured extensively in Polish literature, both in serious critical studies of his life and music and in fictional treatments. The earliest manifestation was probably an 1830 sonnet on Chopin by Leon Ulrich. French writers on Chopin (apart from Sand) have included Marcel Proust and André Gide; and he has also featured in works of Gottfried Benn and Boris Pasternak. There are numerous biographies of Chopin in English (see bibliography for some of these).