Two former prime ministers - Bettino Craxi and Arnoldo Forlani - are among 32 politicians, state managers and businessmen on charges ranging from illegal political party financing to fraud in the biggest trial in the two years of scandals that have rocked the country.
None of the principal defendants, who also include two former ministers - Gianni De Michelis and Paolo Cirino Pomicino - was present as the trial opened in Milan's main courthouse.
Mr Forlani and Mr Craxi, former leaders of the once mighty Christian Democrat and Socialist parties, are on trial together with the heads of three junior parties which for years helped to form ruling coalitions in Rome. Local newspapers have dubbed the proceedings as another 'Nuremberg' after the war crimes trial of Nazi leaders following the Second World War.
But one of the symbols of the political revolution that has swept away the old guard in a wave of popular disgust at rampant corruption will also be in the dock. Umberto Bossi, the leader of the federalist Northern League - one of the three parties in the coalition of the Prime Minister, Silvio Berlusconi, which triumphed in elections earlier this year - is accused of accepting illegal financing for his party.
At the centre of all the accusations is Italy's Ferruzzi group, the troubled foods-to- chemicals conglomerate. Magistrates allege that the group first sought to bribe its way out of a disastrous chemicals joint venture with the state energy group, ENI - the so-called Enimont affair - and then embarked on a systematic programme of influence-buying ahead of the 1992 general election.
Mr Craxi, for whom a Rome magistrate has sought an arrest warrant, was again declared in default by the court after his lawyers said he was too ill to leave his summer home in Tunisia where he has been living for several months. His lawyers say the former Socialist leader, once one of Italy's most influential men, is suffering from heart problems and diabetes.
Under Italian law, defendants do not have to be present in court. But if the court had accepted his plea of illness, Mr Craxi could have forced a postponement of the proceedings. Another Milan court has already declared Mr Craxi, who faces more than 20 different corruption investigations, in default in a separate case and a Rome judge must soon decide on whether to issue an international warrant for his arrest.
The opening sessions in the Milan case will be dedicated to procedural issues, with the main part of the trial getting under way in September following the summer judicial recess.
With a Milan magistrate, Antonio Di Pietro, transformed into a popular hero by the corruption inquiries, heading the prosecution team, the trial is certain to enjoy national attention. An earlier trial stemming from the Enimont affair drew nightly television audiences of several million as Italians tuned in to hear the confessions of the fallen mighty.