Joe Doe / John Doe / Jane Doe

John Doe (male) or Jane Doe (female) are multiple-use placeholder names that are used in the British, Canadian, and American legal systems, when the true name of a person is unknown or is being intentionally concealed. In the context of law enforcement in the United States, such names are often used to refer to a corpse whose identity is unknown or cannot be confirmed. These names are also often used to refer to a hypothetical "everyman" in other contexts, like John Q. Public or "Joe Public"

Και το πιο εντυπωσιακό...

Under the legal terminology of Ancient Rome, the names "Numerius Negidius" and "Aulus Agerius" were used in relation to hypothetical defendants and plaintiffs.

https://en.wikipedia.org/wiki/John_Doe