His coins and those struck under the authority of Eadberht of Northumbria both contained 70 % silver .
Were similar in type and detail , which suggests the possibility of producing a chronology for Beonna 's coins , using the established sequence for the Northumbria coins of Eadberht .
His coins and those struck under the authority of Eadberht of Northumbria both contained 70 % silver and were similar in type and detail , which suggests the possibility of producing a chronology for Beonna 's coins , using the established sequence for the Northumbrian coins of Eadberht .