The Letters of St. Boniface
A rich source of information and opinion on a great variety of matters in the Frankish kingdoms under Charles Martel and Pippin (grandfather and father of Charlemagne) that offers a rare opportunity to get the personal view of someone living in the early medieval period.  --Rosamund McKitterick, Cambridge UniversityThe Letters of St. Boniface constitute perhaps the single most important body of texts dealing with the English missions to the continent in the eighth century, as well as a fine window onto the mind of eighth-century Europe.  --Edward Peters, University of Pennsylvania