These buttons are what you can call Crown and Shield buttons like Lion Crown and Shield or Horse Crown and Shields are the most common ones. The style and make of the button you have is been massed produce in the 20th century even with the no back-mark and shank looking like 19th century. The first two last photos of the horse and lion crown shields are similar style to the button you have and are 20th century the first photo is a typical Crown and Shield button that is from the 19th century.