The "Years of Lead" (anni di piombo) refers to Italy circa 1969-1984, when "something like fourteen thousand acts of political violence, including bombings, assassinations and kidnappings" occurred.
The "lead" in the phrase = bullets.
Similar events took place in other parts of Europe & in Turkey. There's a link with Operation Condor in S. America as well; there are links between the actors.
The period is roughly bookended by the 1969 Piazza Fontana bombing (17 killed, 88 wounded), & the 1980 Bologna train station bombing (85 killed, 200 wounded).
These & other attacks were initially blamed on left/anarchist actors, but eventually found to have been carried out by agents of the right, as part of a "strategy of tension":
"A strategy of tension (strategia della tensione) is an alleged way to control and manipulate public opinion using fear, propaganda, disinformation, psychological warfare, agents provocateurs, as well as false flag terrorist actions."
http://en.wikipedia.org/wiki/Strategy_of_tensionIn 2000, a report from the Olive Tree coalition concluded that the strategy of tension had been supported by the United States:
http://www.cambridgeclarion.org/press_cuttings/us.terrorism_graun_24jun2000.html"In 1998, David Carrett, officer of the U.S. Navy, was indicted by a Milanese magistrate, Guido Salvini, on charge of political and military espionage and his participation in the 1969 Piazza Fontana bombing, among other events. Judge Guido Salvini also opened a case against Sergio Minetto, Italian official for the US-NATO intelligence network, and pentito Carlo Digilio."
Former Italian Prime Minister (& reputed Mafia-linked politian) Giulio Andreotti publicly acknowleged the existence of NATO stay-behind anti-communist organisations in Europe in 1990; it was agents of Gladio & related groups who were responsible for the majority of terrorist violence during the years of lead.
Supposed "left" organizations (e.g. Red Brigades) were infiltrated as well, & high profile cases like the kidnapping & murder of former Prime Minister Aldo Moro, once said to have been the work of the RB, now appear more ambiguous.
http://en.wikipedia.org/wiki/Aldo_MoroSo the cultural & political drama of the years of lead was a kind of masque: things happened, terrible things, but not for the reasons given, not by the actors advertised.
Actors linked to the Italian political establishment, not leftist rebels against it, "killed their own people," completely innocent people, ordinary citizens, for reasons of political manipulation. Not just a few people, but hundreds.