As a scholar of
Anglo-Saxon, he wrote on the
Exeter Book He identified interpolations in the Old English
Bede, by
Laurence Nowell. His work on Nowell included the discovery in 1934, in Nowell's transcription, of the poem
Seasons for Fasting. He translated from the writings of
Tomás Ó Criomhthain, his Irish language teacher on the Blasket Islands, and wrote a memoir,
The Western Island; Or, the Great Blasket (1944), illustrated by his wife Ida. The essay collection
The Irish Tradition (1947) is often cited, and was reprinted in 1994; it includes "Ireland and Medieval Europe", his
John Rhŷs Memorial Lecture from 1927. ==References==