Wow that is one spectacular piece of Kitsch - known in German as Bismarck Kitsch. This is from the time when Bismarck towers and monuments were erected, the family motto "in trinity lies the force" appeared all over the place and objects like your Bierdeckel were made. This would be any time after 1877, until 1914 when the Germans were once more busy doing other things.
The Bierdeckel (tankart) has a Haube (helmet) as a tasteful (..) lid and is enameled with the family crest. The Bierdeckel would have been made at either Köln Ehrenfeld or at Fritz Heckert in Silesia - both specialised in the germanmost enamel retrodesign.
books.google.nl/books?isbn=3640777255 has the full history of beatification of this statesman - in German.