Granit Xhaka has left Arsenal to join German side Bayer Leverkusen in a 25 million euro (£21.4 million) deal.
The 30-year-old Swiss midfielder has signed a five-year deal with the Bundesliga club.
Xhaka, who joined the Gunners in 2016 and was briefly captain in 2019, had a year left on his contract but was expected to leave the club this summer.
Arsenal are on the verge of signing England midfielder Declan Rice in a British record deal from West Ham.
Xhaka scored 23 goals in 297 appearances for the Gunners, helping them win the FA Cup twice and finish runners-up in the Premier League last season.
He scored twice during the final game of the season, a 5-0 home win against Wolves, before being given a standing ovation as he was substituted late on.
That was in stark contrast to an angry confrontation with Arsenal fans after being substituted against Crystal Palace in October 2019, after which he admitted he was close to leaving the club.
That resulted in him being stripped of the captaincy, just over a month after he had been handed the armband by then-manager Unai Emery.
Arsenal rejected a bid of 15 million euros (£12.9 million) for Xhaka from Roma in 2021, and later that summer he signed a one-year contract extension to 2024.
Xhaka previously spent four years playing in the Bundesliga for Borussia Monchengladbach, whom he left to join the Gunners for a reported £35 million in 2016.