Scientists say they've found evidence of key moments in British medieval history, including the assassination of an archbishop, nearly 1,000 miles away in the Swiss Alps. There was no sword buried in the snow. Rather, scientists analyzed lead pollution in laser-carved slivers of ice, each representing a period of days or weeks, from an ice core pulled from the Colle Gnifetti glacier. Between the years 1170 and 1219, lead pollution—believed to have traveled on northwest winds from northern England in summer months—matched levels seen centuries later during the peak of the Industrial Revolution, reports Science. But it wasn't always steady. There was a drop in pollution in 1170 when assassins of King Henry II beheaded Thomas Becket, the archbishop of Canterbury. The church afterward refused to work with the king, per the BBC, and mining came to a standstill.
Tax records show no taxes were paid on lead—used for water pipes, roofs, and windows—that year, archaeologist Chris Loveluck tells Science. But a decade later—once the king was back in the church's graces—mining resumed. That uptick also is reflected in lead pollution in the ice. Another spike was seen in 1193, the year Richard the Lionheart was jailed in Germany by Holy Roman Emperor Henry VI. Researcher Michael McCormick says mining increased as part of "a very concerted effort to pay the ransom." "This is extraordinary—lead levels correlate with the transition of kings," says historian Joanna Story, who wasn't involved in the study published in Antiquity. Others caution that the pollution might not have come from the UK. (Read more discoveries stories.)