Umberto and Umberto
Two similar individuals who switch places are the subject of Mark Twain's story The Prince and the Pauper. One is a king, the other a commoner in poverty. Sounds outlandish and improbable, which is why the tale of Italian King Umberto and restaurateur Umberto is so impossible.
The King, so the tale goes, went to a restaurant to eat. The men were shocked to see how similar they looked when the owner wished to see the monarch. Both their names and their birthdays were the same. On the same day, both got married to Margherita women.
King Umberto was slain the following day after they had a meeting. He received four shots. That day, a second meeting between the two men was planned, but it was never held. The restaurant owner, Umberto, had also been shot that morning and had passed away.
It's a very strange coincidence, if the report is accurate. Without realizing it, the two men could have been identical twins. Yet, the passing of a random restaurant owner in 1900 did not make a lot of news, especially because it occurred on the same day that the monarch was slain. As a result, information about his life—if it ever existed—has been destroyed.