The prosecution had also requested a nine-month prison sentence for Massimo Cacciari, the mayor at the time of the fire, for alleged negligence - but he and seven other people were acquitted.
Venice's La Fenice opera house, which was burned down in 1996, is no nearer being rebuilt - despite the successful conviction of two electricians for arson.
Enrico Carella and Massimi-Liano Marchetti were sentenced to seven and six years respectively for the arson.
The prosecution had also requested a nine-month prison sentence for Massimo Cacciari, the mayor at the time of the fire, for alleged negligence - but he and seven other people were acquitted.
It is the latest twist in a plot as complex, and perhaps as tragic as any of the operas which graced the hall in its 200-year-history.
The recent declaration by the current mayor Paolo Costa that La Fenice will be open in the first half of 2003 will be taken with a pinch of salt by those who have been following the story of the restoration over the last five years.
2001
Only days ago Mayor Costa halted restoration work because the contractor Holzmann Romagnoli was taking so long. He is once more offering the work out for tender.
Romagnoli had been involved in a series of wrangles about deadlines and payments, having asked for a further 30bn Lira (£10m) to finish the work and for penalty payments for lateness to be waived.
The contractor said his employees had to put in extra hours adapting the work of the previous contractor, Impreligo. Holzmann Romagnoli had won the contract from Impreligo following a successful legal challenge.
2000
In August 2000, the projected date for completion of the restoration work slipped from 1 October 2001 to "some time in 2002".
1999
In April of 1999 the Italian authorities finally laid formal charges against the electricians, the mayor and seven others; the electricians had been remanded in prison on suspicion of arson since May 1997.
1998
In August 1998 a charge of negligence against Mayor Cacciari was made in a report by the Venice deputy prosecutor, who said he had to bear "overall responsibility" for the "very serious shortcomings in the running of the theatre, which contributed culpably to its destruction".
The previous month the contractor Impregilo had been forced to hand over the restoration work to Holzmann Romagnoli, following their legal bid.
Holzmann Romagnoli had taken their case to the Italian High Court, alleging that the initial Impregilo bid for the work had been artificially low.
1997
In 1997, a year after the disaster, Mayor Cacciari said the building would be rebuilt by 2000, although fund-raising had already fallen behind schedule.
1996
In June 1996, five months after the fire, Venetian experts concluded that the fire had been started deliberately, prompting Mayor Cacciari to say, "I cannot imagine who could have done such a thing".
Workers had started clearing rubble at the site in May and officials then declared the building would be open "in 1999".
In February 1996, days after the fire, the decision was taken to rebuild the opera house exactly as it was, though there were disagreements as to whether this meant a restoration to the 1792 or the 1836 design.
Fire
On 31 January, with the opera house shell still smouldering, Mayor Cacciari promised La Fenice would be re-opened "within two years" - in other words, during 1998.
The building had burnt down on the night of 29 January.
The Venice fire brigade found themselves hampered by the city's narrow streets and the draining of two nearby canals which limited water supplies.
Pheonix
It might seem that the building is jinxed - it was built on the site a burned-out building and was itself burned down in 1836.
Even the name - La Fenice is Italian for the Pheonix - is redolent of fire.
But despite all the hopes of the world's opera-lovers and the fund-raising efforts of many, including Pavarotti and Woody Allen, this phoenix is finding it very difficult to rise from the ashes.