On Tuesday Mats Hummels completed his controversial transfer from Borussia Dortmund to Bayern Munich.
In doing so, Hummels became the third star to swap Dortmund's yellow for Bayern's blue and red in the past four seasons, following in the footsteps of Mario Gotze and Robert Lewandowski who completed moves to Munich in 2013 and 2014 respectively.
With the frequency of such high profile footballers swapping between two of Germany's main rivals, GiveMeSport thought now would be a good time to remind Premier League fans of some of the most controversial transfers made between two of England's top clubs.
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Having built a reputation for an unwillingness to surrender top talent to fellow domestic rivals, the Premier League has seen a number of contentious and hotly debated moves in recent years...
Robin van Persie - Arsenal to Manchester United in 2012 for a reported fee of £24 million
At the age of 29 and in his prime, Van Persie decided to make the switch between two of the Premier League's oldest and fiercest adversaries in a bid to win a first league title.
At the time, the Dutchman was Arsenal's captain and was coming off his best season as an Arsenal player in which he scored 30 league goals in 30 appearances and announced himself as one of Europe's most talented forwards and sought after commodities.
Manchester United acted fast to poach the striker from their rivals after it became clear he wouldn't sign a new contract with the Gunners.
The transfer undoubtedly left bitter tastes in the mouths of Arsenal fans.
At the time, the north London club were perennial challengers for the Premier League trophy and letting their star striker and leader leave to join one of their biggest challengers left Arsenal supporters wondering what times lay ahead.
Van Persie would go on to win his league title in his first season with the Red Devils, playing a prominent role by scoring 26 league goals and featuring in every league match as Manchester United claimed their 13th Premier League trophy.
On the other hand, Arsenal are still looking for their first title since their unbeaten season of 2003-04, a wait of 13 years and counting.
Verdict: United and Van Persie win this one.
Despite a relatively short stint with The Reds that could be attributed to age or Sir Alex's retirement, RVP won the title he craved and helped Ferguson retire as champions once more. Arsenal are still left wanting.
Fernando Torres - Liverpool to Chelsea in 2011 for a reported £50 million fee
The deal that took a 26-year-old Torres to Stamford Bridge was, at the time, the largest transfer in British league history.
During his time at Anfield, the Spaniard would become one of world football's most lethal attackers. Joining Liverpool from Atletico Madrid for a deal worth around £25 million, Torres scored a total of 81 goals in just 144 appearances (a goal every 160 minutes).
Unfortunately, the Merseyside club's inability to dethrone Jose Mourinho's Chelsea and Ferguson's Man United atop of the Premier League saw Torres seek pastures new and eventually he made the switch to then-champions Chelsea.
However, El Nino was coming off his worst spell as Liverpool player. He scored only nine goals in his 26 appearances for the club prior to making the move after struggling with fitness and injuries. The period had left many unsure whether Torres' best days were behind him.
Torres would go on to have the least productive time of his career at Chelsea. He would net just once in 18 games after his January transfer and strike just 45 times in 172 outings wearing blue.
Meanwhile, Liverpool would turn the money they received in return into Luis Suarez.
Suarez's goals would lead Liverpool to a second-place finish in the 2013-14 season before moving to Barcelona for a rumoured £75 million, as per BBC Sport.
Verdict: Liverpool win this one.
Despite losing a top drawer player and a cult hero, they managed to fetch above market value for Torres and transformed the money into somebody even better (maybe) in Luis Suarez.
Torres would never go on to replicate his Anfield form during his stretch at Chelsea and Liverpool fans are much likelier to look back on this transfer with glee.
Raheem Sterling - Liverpool to Manchester City in 2015 for a reported £49 million fee
In what is, perhaps, the most controversial transfer of the three, a then-20-year-old Sterling swapped Liverpool's red for Manchester City's blue and saw himself become the most expensive English footballer ever.
The move also saw the Englishman's wage rise to an estimated £200,000 a week - The Telegraph.
After flourishing in the 2013-14 season that saw Liverpool finish Premier League runners-up whilst playing alongside Luis Suarez, the teenager's reputation had only grown after the Uruguayan had left and he had become regarded as one of Europe's top youngsters.
Sterling had requested a transfer after Manchester City had two earlier bids turned down in an attempt to force the sale through.
The move infuriated fans who saw the move as a stab in the back after the club had given the winger the opportunity to make the step up to the top flight and had nurtured him into the promising player he was (or is). The transfer was also seen as a move born out of greed on Sterling's part after he had rejected £100,000 a week to extend his stay at Anfield.
City hoped that adding Sterling to their ranks would add pace and width to an attacking line that was lacking both. The Blues also knew adding Raheem, a top English prospect, would ease any future issues with squad restrictions.
After a promising start, Sterling's season had been solid but has not set the world alight.
With one game still to play, Raheem Sterling has featured 31 times in the Premier League for City, scoring six goals and recording two assists.
Verdict: The jury's still out, but you'd have to favour Man City and Sterling.
Despite suffering a tricky first season, City hierarchy knew they were signing potential as much as anything. Sterling has certainly shown promise this year and still has room to improve going forward.
Even though they've endured difficult year, there is no question that Sterling stands more chance of domestic success in Manchester. This will only be enhanced when decorated and coveted manager Pep Guardiola takes the helm.
On the contrary, it's yet apparent whether the money received by Liverpool for the move has been reinvested wisely.
By our book, City are the real winners here because Liverpool never wanted to let the Englishman leave Anfield in the first place - regardless of the fee. They knew the talent they had on their hands and, if they saw a future where Raheem was still in red, they would have pursued it.
With all of England's top clubs set to be hyperactive in the upcoming summer transfer window, can we expect to see any big names moving between Premier League sides?
Which Premier League players would you like to see your team sign?
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