Bleistein v. Donaldson Lithographing Co.
188 U.S. 239 (1903) - full text opinion
You might not think it, but circus posters have a long and interesting history. They're not just an American phenomenon, they exist all over the world.
The poster in the case book is an advertisement featuring the "Celebrated Stirk Family," but there were also Great Wallace Show posters with different subjects. Regardless of how it was advertised, when the circus came to town, it was considered big news.