12th-14th century, German for castle defense. Forged iron star about 3 ¼” driven into spreading roots of trees that surrounded castles. Assaults were on foot, setting ladders and mining the foundations of walls to set fires. The foot irons were concealed just under the soil or covered with leaves. When stepped on, they produced a wound which often resulted in a fatal infection in field conditions. Similar to caltrops which are ineffective in muddy conditions. These could hobbled man or horse in any weather. From a group discovered in a southern German estate arsenal.