Wikipedia
Chrotta
The chrotta, was a musical instrument played in the British Isles, whose exact description is contested.
According to Irish historian Gratton Flood, was a small harp played with a bow. The instrument could be rested on knees or on a table.
Flood notes that the historian Gerbert had described the chrotta as an oblong instrument with six strings, four of which on a fingerboard and two off of it.
Historian Carl Engel noted that a 6th-century CE Italian writer, Venantius Fortunatus, had mentioned the "Chrotta Britanna" in a poem, but did not mention any bow.