Signum manus (sometimes also known as Chrismon) refers to the medieval practice, current from the Merovingian period until the 14th century in the Frankish Empire and its successors, of signing a document or charter with a special type of monogram or royal cypher.
This symbol is a Cross-signature "KAROLVS" of Charlemagne. Charlemagne or Charles the Great (2 April 742 – 28 January 814), numbered Charles I, was King of the Franks from 768, King of the Lombards from 774, and Holy Roman Emperor from 800.
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