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Ilkay Gundogan has left Manchester City with the widely coveted German international signing as a free agent in Barcelona on a contract that could run for three years. The 32-year-old, who City were eager to keep, had interested parties in Saudi Arabia and was coveted by Arsenal but in leaving the Treble winners opted to pursue a career in La Liga, where he has agreed to a two-year contract with the option to extend by a further 12 months.

His buyout clause has been set at €400 million with Barcelona adding a veteran presence to their midfield who can ease the burden on young duo Pedri and Gavi. He will also reunite with former Borussia Dortmund teammate Robert Lewandowski.

Gundogan's seven years in the Premier League saw him etched into City folklore, most notably for the brace he scored on the final day of the season as his side turned around a two-goal deficit against Aston Villa to win the fourth of his five Premier League titles. Gundogan departs having captained City to only the second treble -- Premier League, FA Cup and Champions League -- won by an English side, he himself having scored the opening goal 12 seconds into the FA Cup final.

In an article in the Players' Tribune, Gundogan said,"If I was going to move, there is only one club in the world that made sense. It was Barcelona or nothing. Ever since I was a little kid, I dreamed of wearing that shirt someday. I am confident that I have a few more years left at the highest level, and I just want to help bring Barcelona back to where they deserve to be. It will be a reunion with my old friend Lewa, and I'm excited to play under another manager who I have admired for a long time. When Xavi and I talked about the project, it just seemed so natural. I see so many similarities between us as characters and in the way we see the game.

"I know there's going to be a lot of pressure at Barcelona. But I love pressure. I love to get out of my comfort zone. I was not looking for an easy landing. I was looking for a new challenge. That's what this next chapter is all about."

Replacing Gundogan will prove to be quite the challenge for City. The midfielder was tactically astute enough to adapt to whatever role Pep Guardiola needed him to perform. In recent years, he particularly excelled as a late-arriving runner into the penalty area, delivering 38 goals in all competitions over the last three seasons.

Mateo Kovacic is the man City are turning to, a deal worth up to £30 million having been agreed with Chelsea for his services. The Croatian certainly has many of the qualities that Guardiola most values in his players but he is not the sort to deliver a healthy supply of goals on a yearly basis. He likely will not be able to offer the leadership qualities that made Gundogan so admired at the Premier League champions. Not for nothing did Barcelona term their new signing "one of the world's best midfielders of the last decade." Even with all of City's riches, replacing Gundogan will be a tough task.