Ranking the 5 best transfer windows of all time: Barcelona

#1 Summer, 2003

Ronaldinho became Lionel Messi's mentor at the Camp Nou

The summer of 2003 saw 7 new signings at Camp Nou, but the one name that stood out was 23-year old Ronaldinho.

The Brazilian arrived in Spain with a reputation to match his outrageous talent. He had an instant impact, finishing his debut season as top goalscorer.

He couldn't lead the Blaugrana to any silverware in his first season but won consecutive league titles in 2005 and 2006, and the Champions League in 2006. His individual honours include the Ballon d'Or in 2005, and FIFA World Player of the Year in 2004 and 2005.

In spite of having won only 9 titles at club level, the fact that he is hailed as one of the best Brazilians to ever grace a football pitch is a testament to his abilities. One of the most creative playmakers the sport has ever seen, he went on to embody the flair and elegance that Barca came to be known for in his five seasons in Spain.

He was also Leo Messi's mentor when the young Argentine first broke into the senior team, and every Barca fan will remember his brilliant assist for the then 17-year-old's first goal.

Some other big names who accompanied Ronaldinho in 2003 were Ricardo Quaresma and Rafael Marquez. While Quaresma suffered a short and uneventful career at the Camp Nou, Marquez became the first Mexican to represent Barcelona.

Marquez might not have enjoyed the longevity of Pique or Alves, but he did have an incredibly successful career spanning 7 seasons, winning 10 trophies.

The same season also saw a 19-year-old Andres Iniesta, and 21-year old Victor Valdes become first-team regulars.

Ronaldinho might have been the only stand-out signing of this particular window, but the enormous impact the Brazilian has had in shaping the club's history and perception following the turn of the new millennium means that he will go down in history as probably one of the best pieces of transfer business the Catalan giants have ever done.