AS Roma on Tuesday completed the transfer of Greece international Kostas Manolas from Olympiakos after agreeing to sell Medhi Benatia to Bayern Munich.
The 23-year-old centre-back arrived at Rome's Fiumincino airport from Athens on Tuesday morning and underwent a medical later in the day and later took part in training.
A statement read: "A.S. Roma S.p.A announce that they have signed a contract with Olympiakos Football Club for the permanent signing of the footballer Konstantinos Manolas in a transaction worth a total of 13 million euros.
"The agreement foresees the payment of a variable sum, up to a maximum of two million euros, in bonuses linked to the player fulfilling certain sporting objectives. A contract of a duration of five years has been signed by the player, with an expiry of June 30, 2019."
Manolas, who played four games at the World Cup for Greece this summer, attracted the attention of top European clubs, including Arsenal and Juventus, following a solid 2013-14 campaign with Olympiakos.
He made 25 league appearances last season and scored three goals while he also featured in seven Champions League games for the Piraeus-based club.