The Spaniard joins on a two-year deal having left Liverpool last week after six years in charge at Anfield.
There will be a heavy weight of expectation following a treble-winning season under Mourinho and three championship wins under Roberto Mancini.
Early rumours were quick to suggest BenÃƒÂtez, 50, would be joining another Italian club, Juventus before Luigi Del Neri took the post.
BenÃƒÂtez will be introduced to the public at a news conference on Tuesday 22 June.
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