 However, debasement became a serious issue around the end of the 8th century, when numismatists begin to apply the term "stycas" to Northumbrian coinage (based on a 10th-century gloss in the Lindisfarne Gospels; contemporary terminology is unknown).Both the political and the numismatic chronology of this period is very confused, with many accounts and suggestions competing with one another.By the middle of the 9th century Northumbrian coinage contained almost no silver and was being produced on a massive scale