The league ceremony, which was attended by 50,000 people, culminated a three-day pilgrimage along the Po. Water from the source was poured into Venice's lagoon as a sign of the "Padanian soul". Padania is the league's name for its proposed state. The Italian flag was replaced by a Padanian one and a "government" presented. A "foreign minister" to handle relations with Italy and the rest of the world, a "defence minister" and an "economics minister" to oversee the smooth passage from the Italian to the Padanian lira which yesterday, it was announced, became legal tender at the same rate of exchange as south of the border.
"Nothing is the same as before," shouted Mr Bossi to wild applause. "Nothing can stop what will come. We have strength and constancy on our side."
In Milan, by contrast, Mr Fini's march culminated in a tree-planting ceremony laden with symbols of Italian unity. The big turn-out was a slap in the face for Mr Bossi, who drew only small crowds on his trek across northern Italy to Venice.
It was also an embarrassment for the government of Romano Prodi, which has scorned Mr Bossi's calls for a "republic of Padania" but avoided holding unity rallies. Mr Fini accused Mr Prodi of falling asleep while at the helm of the ship of state. "The Prodi government is like the sleeping beauty ... It's significant that only the National Alliance felt the need to organise a rally like this, because in other countries the response to the secessionist delirium would have been organised by the government."
Right-wing mayors, many of them from the south of the country, which Mr Bossi branded a burden to the nation, delivered patriotic messages before Mr Fini spoke.
He drew the biggest cheer when he said the only people in Europe favouring the break-up of Italy were Nazi-inspired Bavarians who dreamed of a Europe dominated by Germany. He also struck a chord when he said it was time for the authorities to rein in Mr Bossi after he called for the creation of a militia.
At the general election in April the National Alliance won 15.7 per cent of the vote to become Italy's third-biggest party. It is part of the main opposition centre-right alliance.
For the rest of Italy, and the rest of the world, the league's antics in Venice seem no more than another of Mr Bossi's outrageous provocations. But the events of the weekend leave Rome with the dilemma of how to stop the mass movements Mr Bossi has set in motion. On a strictly legal basis, his recent actions are criminal. Moves to split Italy are banned by the Constitution, and formation of a private army carries a 10-year prison sentence.
The only option now is sweeping reform but it remains to be seen whether the political machinery in Rome can achieve this before Mr Bossi and his followers push what is still a peaceful protest movement into something more sinister.