Cotton MS Cleopatra A.iii is an Anglo-Saxon manuscript once held in the Cotton library, now held in the British Library, containing three glossaries which important evidence for Old English vocabulary, as well as for learning and scholarship in Anglo-Saxon England generally. The manuscript was probably written at St Augustine's, Canterbury, and has generally been dated to the mid-tenth century, though recent work suggests the 930s specifically. The manuscript contains three Latin-Old English glossaries.
The First Cleopatra Glossary (folios 5r-75v) is alphabeticised by first letter, drawing on a wide range of sources, including a glossary more or less identical to the Third Cleopatra Glossary, material related to the Corpus Glossary, and a glossed text of Isidore of Seville's Etymologiae. Some of these sources are among the earliest glosses in English, but the Cleopatra reviser (or his source) often revised them. The glossary only gets as far as P: the compilation or copying seems never to have been completed.
The Second Cleopatra Glossary (folios 76r-91v) contains a shorter glossary, organised by subject. A closely related glossary is found in the first three subject lists of the Brussels Glossary (Brussels, Royal Library, 1928-30).
The Third Cleopatra Glossary (folios 92r-117v) contains glosses to Aldhelm's Prosa de virginitate and Carmen de virginitate, with the lemmata in the same order as they appear in the text. It was presumably, therefore, based on a copy of Aldhelm's texts which had interlinear glosses. This glossary or one like it was influential, influencing Byrhtferth of Ramsey and at least one Anglo-Saxon medical text. Kittlick's linguistic investigation showed that some, at least, of the glosses in the Third Cleopatra Glossary are in the Anglian dialect of Old English, with later overlays from West Saxon and Kentish (probably in that order). The glossary--though not necessarily all its entries--must have originated in the eighth century.