Who is that mysterious, elegant man? And why is he sitting on a dead horse? Such are some of the questions sparked by a black-and-white photograph taken in Sheboygan, Wisc., between 1876 and 1884 that has led to nationwide curiosity, speculation and jokes.

It’s a 1870s picture of a mustachioed man in a suit and stovepipe hat who sits rakishly on an expired horse in the middle of a dusty, deserted street.

The picture was included in a newspaper’s 2007 calendar and the response from readers prompted news articles. From there, it took off on the Internet.

“This thing has gotten more mileage than you can shake a stick at,” said Scott Prescher, who has a copy of the dead horse photo in his Sheboygan restaurant.

“It is just a funny picture,” Prescher said. “He is sitting on there with a top hat like he had somewhere special to go and his horse just croaked in the middle of the road.”

No one knows who the gentleman is, exactly what year the picture was taken or the circumstances surrounding it, said Beth Dipple, director of the Sheboygan County Historical Research Center, which has had the picture in its collection for at least 20 years.

“It is a great picture and every time I see it I just laugh,” she said. “But this time the novelty is everybody else is seeing it for the first time. The whole world is seeing it now.”

After writing two stories about the picture, The Sheboygan Press received more than 50 calls and e-mails about it, including from a California genealogist.

Some of the ideas for what the picture depicts include the thoughtful – it was staged for a political campaign perhaps related to sanitation issues – to the bizarre – the horse is being helped to relieve “excess flatulence.”

Dibble said the newspaper published the photo on Aug. 20, 1974, but mainly to focus attention on the nearby buildings. The caption said the man who provided the photo to the newspaper received it from a friend who had no idea about its origin.

A Web site sponsored a contest for readers to write the best caption for the photo and about 100 were submitted, including: “Lay still old girl, FEMA’s on the way.”

Dipple said about all that’s known about the picture is it was taken at South Eighth Street and Indiana Avenue between 1876 and 1884 – based on the bridge over the Sheboygan River in the background and the lack of railroad tracks that were installed in 1884.

The city had laws on the books that required people to stay with their dead horses until they were picked up and disposed of, Dipple said.

“Who knows why somebody would take a picture of it?” she said. “People had weird senses of humor then just like they do now