Thousands of fans and dozens of players turned out on Thursday to say goodbye to Fiorentina captain and Italy international Davide Astori, who died suddenly at the age of 31 on Sunday.

Astori's death left Italian football in a state of shock. All Serie A games were postponed on Sunday, and both Fiorentina and Astori's previous club Cagliari announced they would retire the defender's number 13 shirt.

The funeral was held in Florence's Basilica of the Holy Cross, but the crowd was much too large to fit inside the church, so the audio of the service was broadcast to the fans, many of them crying, who filled the square outside.

Astori's body arrived in a white Maserati hearse as fans waved purple and white Fiorentina flags and held up their team scarves. Purple and white carnations were draped over his casket.

"There's only one captain," fans sang as he was carried out of the church after the service.

Astori, in his 10th Serie A season, was found dead in his hotel room in Udine, where Fiorentina had been due to face Udinese, on Sunday. It is believed that he died of cardiac arrest, according to the Udine prosecutor's office.

Born in Lombardy in northern Italy, Astori became the captain of the Florence team last year.

"He has always been and will always be a Florentine," Cardinal Giuseppe Betori, the city's archbishop, said during his homily.

AS Roma's now-retired attacker Francesco Totti and current Roma player Stephan El Shaarawy were among those who attended the funeral. Astori's last coach for the national team, Gian Piero Ventura, also attended.

Astori made 289 Serie A appearances and played 14 times for the national team.

Florence's city government declared Thursday a day of mourning. Schools and businesses have been asked to observe one minute's silence at 1300 local time (1200 GMT).