turning in his/her grave

[squirelpoo]

when or where does this originate from or what caused this saying.

[jno]

'It would have shocked him so much that it would have brought him back to life' or something along those lines. I don't know when it was first used, though.

[Quizmonster]

The earliest known use of the phrase was in an American publication in the late 19th century. In his American Commonwealth, the writer claimed that...

"Jefferson might turn in his grave if he knew of such an attempt to introduce European distinctions of rank into his democracy."

In other words, as J says above, it applies to anything which the writer thinks would utterly horrify the dead person were he/she still alive.