What is the history behind using impostors? I don't mean impersonators for entertainment, but a likeness for political or security purposes, and when did it go out of fashion?

by testiclelice

I was thinking about the old movie "Dave" and how ridiculous it was, but then I was thinking that as late as the 90s countries were still using impostors quite regularly.

Is there much we know about how long it's been a strategy, and when it was out of fashion among more advanced nations?

Zither13

Was it ever in fashion? Japanese fiction often refefs to the use of doubles to keep important figures safe by drawing fire. Were they actually used? Did any fulfill their function, ie, die or get attacked in place of their principle? Was this ever used anywhere else?