Thousands of protesters from Italy's "Sardine Movement" rallied in central Florence on Saturday, in the latest of a series of gatherings held as a sign of solidarity against the far-right policies of the populist Lega (League) party and its leader, Matteo Salvini.

The grassroots movement is the brainchild of four young Italians from the northeastern region of Emilia-Romagna, which is due to hold elections in January. The wealthy region has been a left-wing bastion since World War II, and was a center of Italy's once strong Communist Party.

Former Deputy Prime Minister Salvini has been campaigning hard in the region, working to recover gains that Lega has lost since last summer. In an attempt to pull down the government in which his party ruled with the anti-establishment Five Star Movement (M5S), Salvini had called for a vote of no confidence, hoping a snap election would propel him to the prime minister's job.

However, his machinations backfired, and M5S has gone on to form a new coalition government with the center-left Democratic Party (PD).

In response to Lega's dogged campaigning, a group of locals in Emilia-Romagna's capital, Bologna, formed the "6,000 sardines" group, hoping to pack that many people into the city's main square in protest earlier this month. To their surprise, more than double that number showed up.

'Salvini's most dangerous enemy'

At Sardine rallies — unlike at most other demonstrations — placards with political slogans or a show support for specific parties are banned. Protesters only carry small signs in the shape of sardines.

After the success of the first Bologna rally, a second was held in the smaller nearby city of Modena, followed by Rimini and Reggio Emilia.

More protests are scheduled to take place in the major cities of Turin, Milan, Naples and Rome. The Rome rally is scheduled for December 14, and organizers hope they can pack 1 million people into the center of the city.

A recent survey by polling agency Index Research found that 40% of Italians consider the Sardines to be "Salvini's most dangerous enemy," above M5S and the PD.

Unlike the M5S, the Sardines are avowed anti-populists and do not have official leaders.