Three Crown China, Germany -- Calling Card Dish -- Restaurant Antoine, New Orleans

Words on front: Restaurant Antoine, Fondee en 1840. Mark on back: Three Crown China Germany. Found quite some time ago, as I recall at an estate sale. Grabbed it to be my souvenir of dining at Antoine's in New Orleans in the early 70's, where I recall having Pompano en Papillote (sp?)--translated to fish (Pompano) baked in paper. Quite a lot of TCC on Etsy and eBay, but most is highly decorative, floral dinnerware except for a very few pieces of a "child's bowl." According to Google, I think this piece goes back to a gentleman in Indiana in the early 1900's. Can anyone fill me in on more than that? Also, because this piece resembles a calling card with the corners turned over, perhaps this piece was placed on the table at Antoine's for people to leave a card when "calling" on friends at table when dining there. ? Either that or a small dish in which to place coins. Size is 4-1/4 X 5-3/4 inches. Don't you just love it?