Italy President Sergio Mattarella
Sergio Mattarella was appointed president of Italy on 31 January 2015Reuters

Sicilian judge Sergio Mattarella has become the new 12th president of Italy, after being nominated by Prime Minister Matteo Renzi.

Renzi's nomination of Mattarella has been seen as a snub towards allies of Silvio Berlusconi.

Mattarella entered politics in 1983, following the murder of his brother, Piersanti Mattarella, the President of Sciliy, by members of the Cosa Nostra – the Scillian Mafia – in 1980.

Mattarella joined Italy's Christian Democracy party – which had been founded by his father, the anti-fascist Bernado Mattarella, in 1943 – in 1983, and was placed in charge of purging Mafia influence from the party.

In 1990, he resigned from a ministerial position, in protest against a law liberalising media ownership rules in Italy, which was seen as a favour for Silvio Berlusconi. He returned a ministerial position in 1999, after being appointed Deputy Prime Minister and the Minister of Defence by then prime minister Massimo D'Alema.

He returned a ministerial position in 1999, as a member of the People's Party, after being appointed Deputy Prime Minister and the Minister of Defence by then prime minister Massimo D'Alema.

Mattarella remained in the Ministry of Defence until 2001, during which time he supported the Nato intervention in the Yugoslavian civil war, and abolished compulsory conscription within the Italian military.

After the People's Party dissolved in 2000, Mattarella was twice re-elected to parliament.

The Italian parliament elected Mattarella a judge of the Constitutional Court in October 2011.

Italy's president is the federal country's head of state, responsible for ensuring Italian politics and laws obey the federal state's constitution.

The president is elected during a secret ballot, and typically remains in power for a seven year term.

While Italy's constitution declares that any citizen over 50, who enjoys civil rights, can be elected president, the role is filled by elder statesmen.