ROME, May 10 (Xinhua) -- Italy's center-left candidate Giorgio Napolitano, was elected the country's 11th postwar president on Wednesday, paving the way for the premier-elect Romano Prodi to form a government.

    The 80-year-old life Senator won 543 votes, well above the minimum 505-vote mark, during the fourth round by more than 1,000 voters to become the first former Communist to win the position.

    Napolitano, a former interior minister and House speaker, is the second-oldest president to take office after Sandro Pertini, who was elected in 1978 at the age of 82.

    The president-elect is to succeed President Carlo Azeglio Ciampi, 85, whose seven-year mandate expires on May 18.

    Italy's president is elected in a joint session by deputies, senators and representatives of the country's 20 regions, totaling 1,010 voters.

    Under the Constitution, the first three ballots require a two-thirds majority to win. If the voting produces no such majority, the rules relax to a straight majority from the fourth ballot on.

    The electors began voting on Monday and the previous three rounds went without a decision. By contrast, outgoing President Ciampi was elected on the first ballot.

    In Italy, the president is a largely ceremonial figure who has the task of giving mandates to try to put together new governments. The head of state is traditionally seen as a unifying figuring in Italy.

    Napolitano's victory also paved the way for center-left leader Prodi to get a mandate to form a government, following his narrow victory in the April parliamentary elections.

    Prodi told reporters earlier on Wednesday that he expected to obtain a mandate between Sunday and Tuesday, with a confidence vote by May 23.

    However, the outgoing premier Silvio Berlusconi refused to give his backing for Napolitano, arguing that his past as a member of the Italian Communist Party (PCI) made him an "unacceptable" candidate.

    Berlusconi raised the same objection to the center-left's first candidate, the former premier and chairman of the Democratic Left party Massimo D'Alema.

    The Democratic Left, of which Napolitano is also a member, is the largest party in Prodi's coalition and the main heir to the PCI.

    "The center-left was united. I'm sorry that the center right failed to understand that Napolitano is truly a president for all Italians. It was a lost opportunity," Prodi said after the vote. Enditem