Charles Plummer's monumental edition of Bede's Ecclesiastical History of England with notes (in two volumes).
This history by Bede (672/3-735) gives an account of Christianity in England from the beginning until his own day. It is considered to be the foundation of our knowledge of British history and a masterpiece eulogized by the scholars of every age. Plummer's edition of this work is compound with Bede's Historia Abbatum and the Letter to Egbert. Bede's remarkable industry in collecting materials and his critical use of them have been admirably illustrated in Plummer's introduction (pp. xliii-xlvii). Plummer's edition opened the way for advances in the study of Bede and the history of Christianity in England.