A golden bull or chrysobull was a golden seal (a bulla aurea), attached to a decree issued by Byzantine Emperors and later by monarchs in Europe during the Middle Ages and Renaissance. The term was originally coined for the golden seal itself but came to be applied to the entire decree. Such decrees were known as golden bulls in western Europe and chrysobullos logos, or chrysobulls, in the Byzantine Empire (χρυσός, chrysos, being Greek for gold).