An amateur metal detectorist has discovered a medieval sword which may have been used by a soldier during the Battle of Grunwald in 1410. Alexander Medvedev discovered the sword near Olsztyn, in northern Poland, alongside a metal scabbard, a belt and two knives. Archaeologists have hailed the discovery as a once-in-a-decade find and it will now be studied and preserved at the museum of the Battle of Grunwald. Scroll down for video An amateur metal detectorist has discovered a medieval sword which may have been used by a soldier during the Battle of Grunwald in 1410 Archaeologists have hailed the discovery as a once-in-a-decade find and it will be studied and preserved at the museum of the Battle of Grunwald