Ardo Smaragdus (died March 843 AD) was a hagiographer.
He was ordained a priest and made head of the monastery school.
and in 814, he replaced Benedict as abbot after the latter joined the imperial court at Aix-la-Chapelle.
[3] Smaragdus wrote a life of Benedict in 822, one of the most reliable hagiological productions of that period.
New York: Robert Appleton Company.