 Representations of the imperial eagle, the emperor and the electors have been common since the rule of Leopold I at the end of the 17th Century.The double-headed eagle, which symbolizes the Empire as a whole, is crowned and given a halo as a sign of the sanctity of the empire.Dedications can often be found on the back of the Imperial Eagle beaker, as well as explanations of the representation, the date of creation and the name of the glass creator.