Romano Prodi's first spell as prime minister lasted two-and-a-half years

But with two spells as Italy's prime minister and a four-year stint as president of the European Commission, the 68-year-old is certainly one of the most prominent.

After the defection of a small party in his centre-left coalition last week, Mr Prodi challenged members of both houses of parliament to "express their judgement" in two separate votes of confidence.

Mr Prodi won the first in the lower house, the Chamber of Deputies, on Wednesday, but the loss of the centrist Udeur party's three seats in the Senate left him without a majority there and he was defeated in Thursday's vote.

He subsequently resigned, but has been asked by the president to remain in a caretaker capacity until he decides whether to call an election or appoint an interim government.

Fragile alliance

The former economist began a second stint as prime minister in April 2006 - at the expense of his predecessor, Silvio Berlusconi - having promised to root out political sleaze and carry out reforms.

Since then, he has battled to keep together a nine-party coalition ranging from communists to Catholics and hold onto its one-seat majority in the senate.

PRODI BIOGRAPHY 1939: Born, Reggio Emilia, Italy 1971-1999: Professor at Bologna University 1978-1979: Italy's minister for industry 1982-1989 and 1993-1994: Chairman of IRI 1996-1999: Italian prime minister 1999-2004: President of the European Commission 2006-2008: Italian prime minister

In February, he resigned following his failure to gain the support radical left-wingers in the coalition over his deployment of Italian troops in Afghanistan and US plans to expand a military airbase in northern Italy.

The coalition had already been shaken by opposition on religious issues, economic reforms, US influence and military funding.

However, Mr Prodi was asked three days later by the Italian President, Giorgio Napolitano, to stay on and survived confidence votes in both houses of parliament.

But despite the apparent backing, the BBC's Christian Fraser in Rome says a cold analysis of Mr Prodi's two years in office shows there were few successes.

Time and again, Mr Prodi was forced to compromise, trimming legislation to please his various suitors, our correspondent says.

And with deep divisions on aspects of foreign policy, fiscal policy or pension reform, it was always a matter of when, not if, this coalition would collapse, he adds.

European record

Mr Prodi's first term as prime minister from 1996 to 1999, leading the "Olive Tree" coalition, made him head of Italy's first genuine centre-left government since the fall of fascism.

Mr Prodi was European Commission president from 1999 to 2004

His main achievement was to get Italy into shape to join the euro by cutting spending and imposing a one-off "tax for Europe".

But that term also came to an abrupt end as a result of the withdrawal of support from the communists.

Mr Prodi went to Brussels next, to become the European Commission president from 1999 to 2004.

He was appointed at a time of crisis - the entire commission had just been dismissed in the wake of a corruption scandal - and is credited with overseeing the introduction of the euro and the enlargement of the European Union.

However, he was often regarded as a rambling professor by comparison with the charismatic Jacques Delors, his predecessor-but-one in the post.

'The sausage'

Mr Prodi was born in September 1939 as the eighth in a family of nine children, seven of whom went on to be university lecturers.

He studied in Milan, London and Stanford before becoming professor of industrial policy in Bologna, the nearest city to his native Reggio Emilia, in 1971.

Romano Prodi, a keen cyclist, used to ride to work in Bologna

He identifies strongly with Bologna, and is known by his political enemies as "the Mortadella" after the rather bland sausage - baloney in American English - for which the city is famous.

His political career first took off in the late 1970s, when for six months he served as Italy's Ministry for Industry in the government of Giulio Andreotti.

He went on to serve as chairman of Italy's powerful state-owned industrial holding company IRI - from 1982 to 1989 and again from 1993 to 1994.

During this period he turned huge losses by this unwieldy collection of more than 100 state enterprises - a relic of fascist times - into profit, and launched a series of privatisation programmes.

He twice came under investigation for alleged corruption while he was head of IRI, but both cases were later shelved as prosecutors failed to establish a prima facie case against Mr Prodi.