Whetstones are one of the most common finds from the Viking Age. What looks like a simple stone however, tells the tale of extensive trading systems - and perhaps even the reason for why the Vikings started raiding overseas.At the end of the 19th century, people emptied the water out of an old quarry in Trøndelag in mid-Norway. Some thought that it might contain a large silver deposit.But the only thing they found were lots of stones. A totally commonplace object...The ordinary stones were whetstones, also known as sharpening stones. They were used to, as the latter name suggests, sharpen...