Atalanta have completed their move for Middlesbrough midfielder Marten de Roon 13 months after selling him to the Teessiders for £12million.
The fee the Italian club has paid for its former player has not be released under a privacy clause.
De Roon's move was confirmed by Boro in a statement released via their official website on Thursday evening.
Under the headline 'Marten de Roon returns to Atalanta', it said: 'The Dutch midfielder has gone back to play in Italy after just one game in the Championship.