The Big Question: What is behind the war dividing Italy's greatest business dynasty?

Why are we asking this now?

Margherita Agnelli, the only surviving child of Gianni Agnelli, the patriarch of the Fiat empire who at one time controlled 4 per cent of Italy's GNP, this week won a key battle in her war with the rest of the family. Italy's highest court ruled that the family's legal dispute over Gianni Agnelli's will could not be heard in Switzerland, as the rest of the family want, but in Italy, in accordance with Margherita's wishes.

So what is the dispute about?

Margherita is furious because she feels she was cut out of arrangments following the death of her 81 year-old father in 2003. After Gianni's death , his widow, Marella, Margherita's mother, transferred to her grandson John, Margherita's son, a controlling stake in Fiat. Margherita says that the shares should have gone to her first. More seriously, in her view, she was never told what her father's fortune was worth at the time of his death.

Details of his Italian patrimony were made public, but the fortune he had squirreled-away in foreign bank accounts, which some believe might amount to billions of dollars, have remained a secret closely held by Gianni's retainers: Franz Grande Stevens, Gianluigi Gabbetti and Siegfried Maron. What makes it all much worse is that Margherita claims these three advisors have treated her with contempt. She claims Mr Gabetti told her at one tense family meeting: "You are not worthy to be Gianni Agnelli's daughter. You are not worthy even to wish it."

So Margherita was left poverty-stricken on her father's death?

Well hardly. Feel free to put away your hankies. Her mother says that Margherita obtained "abundant compensation from me, sufficient to

guarantee a serene future for her and her children". Margherita, who lives in Geneva with her second husband, a count of Russian origins called Serge de Pahlen, does not dispute that. She has said repeatedly that this is "nothing to do with money". "I am in need of information," she said last year, when the case erupted in the courts. "I have never received, despite repeated requests, the details of the inheritance of Gianni Agnelli.

"I only ask – I who am, along with my mother, the only direct heir – to be told the situation regarding the inheritance left by my father." Despite the vast wealth, the temptations of self-indulgence of every sort and the presence of a rich cast of wild men and eccentrics, the Agnellis retained an impressively united front, at least in public, up to the time of Gianni Agnelli's death.

How did the family firm become so rich and important?

Like the other moguls of the motor industry around the world, they got in on the ground floor. Gianni's aristocratic grandfather Giovanni, born in 1866, founded Fabbrica Italiana Automobili Torino in 1899, initially to manufacture motorcycles under licence from a French company, and found himself in the thick of the motor car boom. Within a few years Fiat had become the predominant Italian auto firm.

So the empire dropped into Gianni's lap?

It wasn't quite that simple. Gianni was certainly born with the proverbial silver spoon, but both his paternal grandparents and his parents died in accidents – his parents when they were still in their forties. Gianni, who had carved a swathe through the drawing rooms of the Western world as Italy's most eligible playboy, was suddenly forced to turn serious. By the age of 45, in 1966, he was chairman, a position he retained for the rest of his life, becoming Italy's uncrowned king, a permanent and profound influence on Italian economic and industrial policy, and a symbol of style and success for generations of Italian boys.

What did he achieve?

First and foremost, the Fiat 500 – which the company attempted with some success to replicate earlier this year with the launch of the new 500 – was developed under his leadership. This was one miniature stroke of genius in an industrial empire of stupendous proportions. At its height the firm had ten major divisions and included hundreds of companies involved in areas as diverse as banking, insurance, real estate, chemicals, aerospace, telecoms, defence electronics and armaments, confectionery and Vermouth. Fiat also owned Juventus, the most successful football team in Italian history.

What was his management style like?

He certainly worked hard, and his feet barely touched the ground, but at the same time he contrived to perpetuate the image of the ultimate pleasure-loving jetsetter with his magnificent yachts and friendships with the likes of the Kennedys and Henry Kissinger. Yet the future of the family was dear to him and he presided over the creation of heady dynastic liaisons with the Furstenbergs from Bavaria and the Brandolinis from Venice. At the same time, Fiat became the ultimate paternalistic employer, "La Mamma" as it was known in Turin, pampering tens of thousands of employees with free housing, health care, holiday resorts and kindergartens.

Did he have much time left over for his family?

Margherita does not complain that he was neglectful. "It's not true that he was an absent father," she said last year. "He was present like all fathers of his generation, for whom child-raising was the exclusive task of the women. But I have many memories of his tenderness. And I treasure them."

So until Margherita's lawsuit it was just one big happy family, right?

Sadly not. Being born into the Agnelli clan meant one was expected to shine. Those who proved they were worthy of the name were accepted. But those who were not could be cruelly discarded. Most tragic of the failures was Edoardo, Margherita's elder brother and Gianni's only other heir. After he gave an interview to Italian press in which he claimed that he was Fiat's heir apparent, Gianni announced that his own brother Umberto would be his successor and later restructured Fiat to keep it out of Edoardo's hands.

Aged 46, Eduardo committed suicide, throwing himself from a bridge in Turin.

Was family warfare brewing during Gianni's lifetime?

Possibly below the surface, but his autocratic, oversize personality succeeded in holding the clan more or less compact through every difficulty it encountered. As his relative Delfina Rattazzi has said: "It is a family for the strong."

So has the legal wrangling disgraced the family name?

Margherita claims otherwise. After launching the lawsuit against her closest relatives and their advisers, she said: "I'm sure my father would be very proud of me."

Can the Agnelli family settle their differences?

Yes...

* The rest of the family will finally see off their presumptuous retainers

* With the Fiat share price dropping again, Margherita will lose interest in the family fortune

* Gianni's rule of family unity, deeply entrenched over generations, will prevail in the end

No...

* It is a feud that had been brewing for years before it erupted

* The sums of money are too colossal for either side to back down or try to reach an amicable settlement

* The rupture has gone too far – which is why the rest of family now refer to Margherita as "Signore de Pahlen"