A five-minute primer on an issue making headlines The capture of Italian mafia boss Bernardo Provenzano has thrown the Cosa Nostra back into the international spotlight. We've all seen The Godfather and love The Sopranos, but where does the real mafia come from? You have to go back about 170 years to find its origins in Sicily. What started as an extortion and protection racket in Palermo's orange and lemon farms became a secret criminal society that infiltrated the business and government elite. For decades the mafia was ignored or tolerated. Mafia comes from mafioso, which means members were 'cool' or 'beautiful'. The killings, intimidation and sordid criminal activity was explained as a peculiarly Sicilian way of looking after one's interests. How did the mafia become so big in the United States? It is a consequence of Italian immigration that started in the late 19th century. Initial power was concentrated - and still is - around New York, but spread to other cities. After many bloody turf wars, families like the Bonannos, Gambinos and Genovese dominated. By the mid-20th century the American mafia was reputed to have infiltrated many labour unions: the mafia built Las Vegas. There were also links with politicians, including president John F. Kennedy. Most people's knowledge of 'the mob' is from television and films. Has that had much effect on the real thing? It's not so much life imitating art as both getting stuck in an almighty tangle. Actors on The Sopranos complain some people think they are real mobsters, while some real mobsters are said to copy the traits and language of their favourite screen mafia. Although the Italian mafia is still recognised as the most powerful organised crime group in the US, many analysts believe it is a shadow of its former self. The notoriety lives on in films and television. Newspaper articles that bring the two together also draw the ire of law-abiding Italian-Americans, who complain of misleading cultural stereotypes. Is it compulsory to have a nickname if you're a mafioso? If you want to enjoy wider notoriety, it helps, but nicknames tend to leave little to the imagination. It's not too hard to guess why Al Capone was known as Scarface. Before his arrest last week, Provenzano was called 'The Accountant', for his abilities handling the business side of the empire. In his youth, it was 'Bernie, the Tractor', because of the way he mowed down rivals. The man most tipped to be his successor is Matteo 'Diabolik' Messina Denaro. What's likely to happen to the Italian mafia now? The jury's out. After a government-led blitz in the 1980s, Provenzano is said to have initiated a move away from violence to maintain profits. White-collar crime, university educated mafioso and women were said to be coming to the fore. But 43-year-old Denaro is regarded as more trigger-happy.