There was the bombing of a Milan bank in 1969 that killed 16 people. There was the kidnapping and murder in 1978 of Aldo Moro, a former prime minister. There was the 1980 bomb that blew up 85 people at Bologna railway station. But of the terrible, politically related crimes that stain Italy's post-fascist history, the violent death of Roberto Calvi has a good claim to be the most mysterious of the lot.

Calvi, chairman of Banco Ambrosiano, a bank that went bust soon after his death, was known as "God's banker" because of the illicit financial dealings that connected him to the Vatican's bank, the Istituto per le Opere di Religione (IOR).