Enrico Berlinguer was the secretary of the Italian communist party between 70s and 80s, leading his party to huge numbers (like almost 40%) for a left wing party in a conservative country like Italy.
Together with Aldo Moro, secretary of Christian Democrats, the major party in Italy at the time, he was responsible for the so called "Historic Compromise", a kind of large alliance between all parliament forces toward a fruitful collaboration for a better government and to lower the various social turmoils and violence. This Compromise failed when Aldo Moro was kidnapped and then killed by extreme left terrorists (Brigate Rosse, Red Brigades).
Berlinguer was a leader beloved by pretty much anyone, probably the most important and surely the last one in Italian politics history.
Recently, Beppe Grillo said that M5S is carrying on Berlinguer's political spirit. A thing that doesn't make any sense at all, considering M5S was born pretty much to destroy and replace the current political class with non-politicians, and now that his party is in the parliament, his main course of action is basically to undermine any other proposal just because it comes from the corrupt political class it's fighting. So, like, the complete opposite of the Historic Compromise.
To this, add the fact that a lot of M5S supporters come from fascism, and even a lot of the party itself ideas draw from it (it's not a coincidence Front National or Golden Dawn are somewhat close to M5S).
So hell, it's not that weird that the Democratic Party (current heir of Berlinguer's Communist Party, even if extremely watered down) leader, Matteo Renzi, is kinda angry when Grillo is exploiting Berlinguer's memory to gain left wing votes.
