Cristiano Ronaldo - Manchester United with Barclays player of the month award

On 12 August 2003, Sir Alex Ferguson unveiled his new signing, the 18-year-old Cristiano Ronaldo.

Cristiano Ronaldo - Manchester UnitedCristiano Ronaldo in his early days with Manchester United

The teenager was snapped up for £12.24 million, making him the most expensive teenager in the world - a record that didn't last long with United alone having snapped up Anderson (£22 million), Wayne Rooney (£26 million), Luke Shaw (£31 million) and Anthony Martial (£36 million) in recent years.

Ferguson had been in pursuit of Ronaldo for a while, but had to accelerate proceedings as other sides became interested in the Portuguese teenager. 

The manager's interest in Ronaldo was sealed on 7 August, when he ran rings around John O'Shea during a pre-season friendly for Sporting Lisbon, starring in a 3-1 win over the Red Devils

The Guardian reported that the match was "meaningless", but hindsight has shown that the match had huge ramifications for the future of European football.

Upon signing the youngster, Ferguson said: 'He is an extremely talented footballer, a two-footed attacker who can play anywhere up front: right, left or through the middle.'

Cristiano Ronaldo - Manchester United with Barclays player of the month awardIt took time for Ronaldo to scale new heights for his club

Ronaldo was assigned the number 7 jersey vacated by David Beckham that summer, but initially struggled to live up to the hype that surrounded him.

He was often lambasted for not passing to his teammates and showboating. His role in getting Wayne Rooney sent off during Euro 2004 - an incriminating wink to the Portugal bench wasn't particularly well disguised - didn't help ingratiate himself to the United faithful, though the incident proved not to have too damaging an effect.

Though Ronaldo is now renowned for his tremendous feats of goalscoring, he was not always quite so prolific.

In his first four seasons at the club, he scored 50 goals for United. But in the 2007/8 season, Ronaldo reached new heights, scoring 42 goals in all competitions and helping United lift the Premier League and Champions League trophies.

Despite rumours that he would leave for Real Madrid, he remained at Old Trafford and scored 25 goals the following season, winning the Premier League for one final time but losing in the Champions League final to Barcelona.

Ronaldo was finally granted his wish during the summer of 2009 as he signed for Real Madrid in a world-record £80 million deal. 

Cristiano Ronaldo Signed to Real MadridRonaldo is unveiled as a Galactico

His goalscoring feats at the Bernabeu have been scarcely believable. He has scored 351 goals in 304 appearances for the club, winning the Champions League twice and the Ballon d'Or on three occasions.

This summer, he finally achieved success on the international front as his Portugal side - shorn of their talisman through injury minutes into the final - defeated the hosts France 1-0 to win Euro 2016. 

Since that fateful day 13 years ago, Ronaldo has evolved to become one of the world's most complete players, vying with Lionel Messi year-on-year to be crowned the world's best player.

For the player revealed alongside Ronaldo on 12 August 2003, things didn't work out quite the same.

Ronaldo scores for Brazil in the 2002 World Cup FinalThe other Ronaldo may have scored the goals, but Brazil's 2002 World Cup win was attributed elsewhere

Ferguson announced not only the signing of Cristiano Ronaldo but also of world cup-winning midfielder, Kléberson.

The 24-year-old Brazilian was signed from Atlético Paranaense for £6 million, having been given a ringing endorsement from Brazil manager Luiz Felipe Scolari.

Kleberson  - Manchester UnitedKleberson - Manchester United

Scolari had said that Kléberson 'was always the first name on the team list, ahead of players like Ronaldo.'

He could only muster 20 league appearances during his two seasons at the club, before being sold to Beşiktaş for £2.5 million.

The 37-year-old Kléberson can now be found playing in America for the Fort Lauderdale Strikers. 

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