Former Arsenal defender Sokratis has completed a free transfer to Olympiakos on a contract until the summer of 2023.
Arsenal and Sokratis agreed to end the defender's contract at the Emirates six months early, before he completed his move to Greece a few days later.
The 32-year-old's deal was set to expire at Arsenal at the end of the season. Sky in Italy has reported that La Liga clubs Real Betis and Sevilla, as well as Serie A side Genoa, were keen to sign the Greek international.
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He joined Arsenal from Borussia Dortmund in July 2018 and went on to make 69 appearances for the club.
However, along with Mesut Ozil, Gunners boss Mikel Arteta chose not to include Sokratis in his plans this season and left the pair out of Arsenal's Premier League and Europa League squads.
Ozil, Sokratis and defender Sead Kolasinac have all left the club this month with speculation also surrounding the future of Shkodran Mustafi.
Arsenal have agreed a deal to sign Real Madrid midfielder Martin Odegaard on loan until the end of the season - but what will the one-time wonderkid bring to the Emirates Stadium and where will he fit into Mikel Arteta's team?
The Norway international is now 22 but hit the headlines in 2015 when he was signed by Real as a 16-year-old, with comparisons to Lionel Messi being made about his ability.
While his career has not taken off as Messi's did, his development has taken some encouraging strides forwards in recent seasons and Arteta and Arsenal supporters will be excited to see what he can produce in the Premier League.