Italy has had its fair share of high-profile trials, and plenty of allegations of the state being in cahoots with the mob, — but never before had a standing president participated in a mafia trial. Until today.

Giorgio Napolitano, Italy's 89-year-old president, testified for more than three hours before Sicilian judges who interviewed him at his official residence in Rome. The president — who is not accused of any crime — was called in as a witness to alleged negotiations between the Italian government and the Sicilian mafia in the 1990s.

Under oath, Napolitano, who has been at the helm of the republic since 2006 but held another official position at the time of the alleged negotiations, denied having any knowledge of them. He responded to questions with the "maximum amount of transparency and serenity" and without invoking his constitutional right to remain silent, according to a statement released by his office.

"He said he had been a spectator to the events, nothing more," Luca Cianferoni, attorney for a notorious mafia boss told reporters after leaving the hearing — which was closed to the press, a decision Italian journalists protested.

The trial takes on conversations that allegedly took place in 1992 and 1993 between Italian ministers and police and the Mafia, following a wave of bombings and assassinations that culminated in the death of anti-mafia prosecutor Giovanni Falcone, his wife and three bodyguards, killed in May 1992 after their car drove over a bomb the mafia planted under the road.

Prosecutors in the case claim that government officials tried to make a deal with the mafia following that incident, including by promising less severe treatment in jail in exchange for an end to the violence. They maintain that the state's willingness to talk to the mafia actually encouraged their violence — including the assassination, two months later, of another anti-mafia prosecutor and a colleague of Falcone, Paolo Borsellino, killed by a car bomb. The bombings continued into 1993, claiming more victims.

Falcone and Borsellino have become icons of Italy's battle with the mafia and their assassinations mark two of the most traumatic moments of the country's long history with the organized criminal organization.

Several people are on trial for the alleged negotiations, including former interior minister Nicola Mancino, who denies all charges, and Salvatore "Toto" Riina, one of Italy's most notorious bosses and a member of the Corleone mob family.

Eighty-three year old Riina — also known as "the Beast" for his brutality — is serving several life sentences, and continues to be charged with past crimes as more cases make it to trial. In his career has a mobster, Riina is believed to have killed dozens of people and ordered the death of hundreds, including those of Falcone and Borsellino.

Riina's lawyer, Cianferoni, also asked Napolitano some questions, which the president answered even though the court had ruled them inadmissible.

"If you consent, I'd like to please the attorney," the president reportedly said. The president also encouraged the court to release a public transcript of the hearing as soon as possible.

Other lawyers in the trial, including that of the former director of Italy's intelligence agency Mario Mori, declined to question Napolitano out of "institutional respect."

Prosecutors asked Napolitano about a letter from 2012 from one of his legal advisors referring to "unspeakable agreements," which they said implied the president might have known about the talks with the mafia.

Napolitano had originally provided written testimony but declined to testify in the trial saying he had no "useful knowledge" to contribute. He agreed to today's hearing after the court ruled that his testimony would be "neither superfluous nor irrelevant," Reuters reported.

A verdict in the trial is not expected for another two years at least.