Arsenal have completed the signing of Italy defender Riccardo Calafiori from Bologna as Emile Smith Rowe departs the Emirates Stadium.
Calafiori, 22, was highlighted as a priority target for the Gunners this season and they have landed their man for a fee of £42million.
Calafiori has signed a five-year deal at the Emirates having played for Italy during their Euro 2024 campaign.
"We welcome Riccardo and his family to Arsenal. He is a great signing and gives us huge strength to reinforce our defence," said manager Mikel Arteta.
"Riccardo is a big personality and character, with specific skills which will make us stronger as we push to win major trophies.
"He has already shown great development in recent seasons with his performances for both Bologna and Italy, with his progression and development in the past year being really impressive.
"We're looking forward to working with Riccardo, integrating him into the squad, and supporting him in the years to come."
Calafiori, who can also operate at left-back, becomes Arsenal's second major summer acquisition after David Raya's loan move from Brentford was made permanent.
Calafiori has already joined up with his new team-mates on their tour of the United States and said Arsenal is the "perfect place" for him.
Asked what he can bring to the club, he said on Sky Sports News: "Maybe my mentality, I like to win, I want to give this to the team.
"I am confident with the ball, I like to play, this is the perfect place for me."
While Calafiori has come in, England international Smith Rowe has left for London rivals Fulham.
The 24-year-old, a Hale End academy graduate, struggled to break into the first-team with a number of injuries also hampering his progress.
Smith Rowe made just 13 Premier League appearances last season and the PA news agency understands a deal worth up to £34million has been struck with Fulham, with £27m paid and a further £7m in potential add-ons making it a club-record deal for the Whites.