LAMEZIA TERME, Italy — An Italian tribunal on Monday convicted 207 people and sentenced them to a combined 2,100 years in prison on charges related to their membership in Italy’s ’ndrangheta organized crime syndicate, one of the world’s most powerful, extensive and wealthy drug-trafficking groups.

It took over an hour and 40 minutes to read aloud the court’s lengthy verdict, including the acquittal of 131 defendants. The drama unfolded in a bunker-style courtroom in the southern Calabria region, where the mob organization was originally based.

The ’ndrangheta has quietly amassed power in Italy and abroad as the Sicilian Mafia lost influence, and it now holds almost a monopoly on cocaine importation in Europe, according to anti-mafia prosecutors who led the investigation in southern Italy. The organization also has bases in North and South America and is active in Africa, Italian prosecutors maintain, and ’ndrangheta figures have been arrested in recent years around Europe and in Brazil and Lebanon.

The defendants had been charged with crimes that include drug and arms trafficking, extortion and mafia association, a term in Italy’s penal code for members of organized crime groups. Others were charged with acting in complicity with the ’ndrangheta without actually being a member.

The charges grew out of an investigation of 12 clans linked to a convicted ’ndrangheta boss. The central figure, Luigi Mancuso, served 19 years in an Italian prison for his role in leading what investigators allege is one of the ’ndrangheta’s most powerful crime families, based in the town of Vibo Valentia.

Vincenzo Capomolla, deputy chief prosecutor of Catanzaro, said prosecutors’ overall case held up with the convictions and confirmed the stranglehold the ’ndrangheta held on Vibo Valentia.

“The infiltration of the criminal organization in the province of Vibo Valentia was so deep-rooted and so widespread, so alarming, so disturbing that I think it can be noted that there was no aspect of the life of the social economic fabric of the province that was not conditioned by the capacity of the force of intimidation of this so dangerous criminal organization,” he said.

Giuseppe Di Renzo, defense attorney for several of the defendants, noted that more than a third of the original defendants were fully acquitted, while others were found not guilty of some charges.

He criticized the disparate and large number of defendants, saying they showed there was no cohesive thread to the case.

Based almost entirely on blood ties, the ’ndrangheta was mostly immune to turncoats for decades, but the ranks of those turning state’s evidence are becoming more substantial. In this trial, they included a relative of Mancuso’s.

Several dozen informants in the case came from the ’ndrangheta, while others formerly belonged to Sicily’s Cosa Nostra.