Ronaldinho could be the next.
Besiktas are believed to be the frontrunners to sign the Brazilian, further emphasising Turkish football's capability of using money as a source of prestige. When Celtic line up against Trabzonspor in the Antalya Cup, they could face Florent Malouda, Didier Zokora and Jose Bosingwa, and the club has also been linked with moves for Dimitar Berbatov and Lucas Piazon, the Chelsea attacker. By importing glamour, Turkish football has renewed its image.
Ronaldinho's transfer from Atletico Mineiro is not confirmed, and he has other suitors, but Turkey remains the most likely destination. He will join Didier Drogba and Wesley Sneijder, signed for Galatasaray last January, and Dirk Kuyt and Raul Meireles, both at Fenerbahce. Homegrown players still dominate the squads of even the leading sides, but Turkish football now seems awash with cash.
It is not beyond reproach, since Trabzonspor were one of six clubs who were told by UEFA last September that their European prize money would be temporarily withheld for failing to comply with financial regulations. Besiktas were banned from competing at all in Europe last season for similar reasons. None the less, Turkish football is not short of the kind of funds that persuades players to overcome concerns about moving to a country not among the top five football nations in Europe.
And there is more to it than the money. When Sneijder signed for Galatasaray, he had other offers, including some more lucrative from the Middle East, but he was advised by Jose Mourinho and Louis van Gaal to make the move.
Football generates fervour in Turkey, as the country's most popular sport by some distance. Popular players are treated like heroic figures, which combined with wages that can reach up to £100,000 a week makes an alluring proposition. Ronaldinho could earn up to £10m over a two-and-a-half year contract.
Each club has different financial circumstances, and most in Turkey are owned by their members, or fans, rather than a rich benefactor, but set up public limited companies to manage the football clubs.
Investments can be made to fund projects, though, usually by the club president, and the tax rates are also extremely favourable compared to other European countries, with a top rate for footballers of 15% and the players being paid net rather than gross amounts. Sponsorship deals have also generated huge amounts of revenue for the leading Turkish clubs - Besiktas are believed to have signed a £120m contract last year, as well as a recent deal with adidas, and one of the club's sponsors is thought to be footing part of the bill for Ronaldinho - but media revenues have also increased.
In the last 16 years, money from television contracts has risen 40-fold, with the deal for next season expected to generate somewhere in the region of £360m.
"During the last 15 years, the three Istanbul clubs - Galatasaray, Fenerbahce and Besiktas - are leading in new ways of generating revenues," says Alp Ulagay, an editor at Hurriyet newspaper. "TV money has spiralled upwards, new arenas were built, and more commercial revenues discovered. Since 2010, Super League clubs are getting more than £250m media rights money per season. Half of it goes to the big clubs. The commercial money is around £80m, including betting rights. Even the smallest team can have an annual budget of £8m-10m."
Even so, it is not all unblemished. Some shareholders complained to the regulatory authorities about the share issue that allowed Galatasaray to raise around £30m three years ago. The share issue was structured in such a way that shareholders had to pay an additional amount to maintain the size of their stakes after it was revealed that the stadium, and therefore its revenues, were owned by the club, rather than its parent company. It was described as a piece of "financial engineering", and it certainly contributed to the financial might that allowed the club to move for Drogba and Sneijder.
Debt is also an issue, with Galatasaray owing £200m.
"Galatasaray and Fenerbahçe have no payment problems," says Ulagay. "But Besiktas were banned from Europe due to non-payments. Some of the smaller clubs have similar issues as well. They are mostly losing money due to excessive payments to players and their agents."
Turkish football has been transformed in the past 20 years, but with increasing amounts of money comes more problems to deal with.