He is almost certainly not the original writer of Beowulf, but he
transcribed an earlier Anglo-Saxon poem and may have been the one to
imbue it with Christian sensibilities.
The works of this anonymous monk and all other monks of that time were
scattered and nearly eliminated during Henry VIII's disolution of
Catholic monasteries circa 1560.
Most likely a monk/scribe working in pre-Norman times, quite possilby
in Northumbria or Mercia, as a Mercian king is given a glowing mention
at one point in the poem.