Libellus responsionum
The Libellus responsionum (Latin for "little book of answers") is a papal letter (also known as a papal rescript or decretal) written in 601 by Pope Gregory I to Augustine of Canterbury in response to several of Augustine's questions regarding the nascent church in Anglo-Saxon England. The Libellus was reproduced in its entirety by Bede in his Historia ecclesiastica gentis Anglorum, whence it was transmitted widely in the Middle Ages, and where it is still most often encountered by students and historians today.