Giulio Mazzarino was born on 14 July 1602 in Pescina in the Abruzzo province of Italy, about one hundred twenty kilometers from Rome. His parents were residents of Rome, spending the summer in Pescina to escape the summer heat. His father, Pietro Mazzarino (1576-1654), had moved to Rome from Sicily in 1590 to become a chamberlain in the family of Filippo I Colonna, the Grand Constable of Naples. His father became a citizen of Rome in 1608. His mother Ortensia Bufalini (1575-1644) was a native of Rome, from a Bufalini family of the nobility whose origins were in Città di Castello in Umbria. The family had moved to Rome in the Middle Ages. She was the goddaughter of Filippo I Colonna, her husband's employer. Giulio was the eldest of six children, two boys and four girls.