Anglo-Saxons played a full part in continuing the ancient literary tradition of letter-writing and letter-collecting. Seventh- and eighth-century England already displays all the main medieval types of letter. There are purely practical communications, such as the letter of Wealdhere, bishop of London, to Archbishop Berhtwald in 704×705, and semi-public treatises in epistolary form, such as Bede's Epistola ad Ecgbertum. There are also numerous letters of friendship, congratulation, exhortation, encouragement, or condolence, notably in the collected correspondence of Aldhelm, Boniface and Lull. The originals of even practical letters stood little chance of being preserved, since they had no value as legal instruments, unlike charters. Indeed, a twelfth-century Canterbury archivist endorsed ‘Epistola inutilis’ on Wealdhere's letter, and it is a happy accident that it has survived; it is the oldest extant letter on vellum or parchment in Western Europe. Fortunately, however, letter-collections in book form were sometimes made, either because of the writers' importance or because of their letters' value as models of style. Education in letter-writing was clearly based on imitation. This is well conveyed by a letter which Boniface received soon after 732 from Leofgyth, a nun at Wimborne in Dorset. She concludes by asking Boniface to correct her rustic style and to send one of his own letters as a model (exempli gratia); she then adds four lines of halting verse (in formulae culled from Aldhelm), which she had