It feels like an early retirement, but Cristiano Ronaldo has already made an impact on the game that few in world football will be able to match.

No cash-grab in the Middle East, acrimonious departure from Manchester United, or World Cup disappointment can detract from his on-field achievements.

The 37-year-old's transformation from rangy, flashy winger to toned goalscoring machine has been an incredible feat of skill, determination, reinvention and dedication.

Five Ballon d'Or gongs, seven domestic league titles, five Champions League trophies, and a European Championship go along with an astonishing 819 career goals so far. He's officially the game's greatest ever goalscorer.

Ronaldo sadly leaves Europe under a cloud of controversy following a stroppy interview with Piers Morgan, which ended his United career, and a fallout with Portugal coach Fernando Santos, which extinguished his final World Cup dream.

It has been a wild end to 2022 for Ronaldo, in a year which began with a great personal loss. Yet in the decades to come, his on-field legacy will prevail thanks to a career where he inspired millions through an obsessive drive for perfection.

From show pony to world's best

It took Ronaldo time to fulfill his raw potential in Manchester and the catalyst started with a cheeky wink.

Ronaldo returned to England from the 2006 World Cup a villain after his role in getting Wayne Rooney sent off in Portugal's quarter-final win over the Three Lions. The then 21-year-old was vehemently booed throughout the Premier League season.

He'd developed a reputation as a show-pony winger in his first three campaigns at Manchester United, capable of the spectacular but with a fiery temperament and inconsistent end product.

Yet following an incident which could have derailed his career in the Premier League, Ronaldo used it instead as motivation to kick-start his metamorphosis. He returned to England with a different physique and a different mindset. The mazy runs, stepovers, and trademark "chop" move were soon complemented with physicality and goal scoring prowess.

Two years on, in 2008, Ronaldo was crowned best player in the world after scoring 42 goals and winning the Premier League and Champions League. He transformed United back into a European powerhouse and proved his detractors wrong.

Ronaldo managed just 27 goals in his first 137 games at Old Trafford, but finished with 118 goals in 292 matches and a third consecutive Premier League title. He headed for Real Madrid in 2009 on the brink of greatness.

Champions League king

In Spain, Ronaldo cemented his place in the debate over football's greatest ever player.

He took up a role on the left wing, with freedom to roam centrally, and his goal tally exploded. Ronaldo netted 50-plus goals for the next six seasons as he thrived on Madrid's transitional style of play.

It was during this period that he also developed a leadership role in the dressing room and dedicated more time to preserving his body.

In nine seasons, Ronaldo would only lift La Liga twice, but it was in Europe where he truly left his mark. He delivered La Decima for Madrid in 2013-14 and then won three more consecutive Champions League titles.

In between, he helped Portugal to a memorable victory in the Euro 2016 final against France.

When Ronaldo departed Madrid for Juventus in the summer of 2018 he was the club's all-time top goalscorer with 450 in 438 matches.

Gradual decline in later years

At the age of 33 Ronaldo had to adapt to a new league in a team that played a different style of football and was transitioning after domestic domination for close to a decade.

The three-year spell could be seen as a personal success with Ronaldo smashing home 101 goals in 134 games and winning two league titles. But he was there to win the Champions League, and Juventus fell disappointingly short, losing to Ajax, Lyon and Porto as they failed to make it past the quarter-finals in three consecutive seasons.

He may have collected an impressive goal haul but when Ronaldo left Juventus in 2021 the club was in worse shape than when he arrived.

It's unfortunately been a similar story during his emotional return to Manchester. Despite scoring 24 goals in his first season back, United fell well short of Champions League qualification and his relationship with the club gradually deteriorated as his influence waned.

Controversies mar Ronaldo's reputation

Ronaldo's ignominious end at Manchester United was all his own doing and he similarly tarnished his reputation with Portugal thanks to his antics in Qatar.

Together with other on-field and off-field strops, tax evasion charges in Spain and rape allegations from 2005 and 2009 (which were both dismissed) Ronaldo has not been far from controversy during his career. His move to Saudi Arabia has also brought accusations that he is abetting sportswashing.

Ronaldo's claim to talk show host Jonathan Ross back in 2015 that he wanted to "finish with dignity in a good club" has also come back to haunt him.

Minds can change quickly, of course, and Ronaldo has faced an emotionally challenging last eight months after he and wife Georgina announced their son Angel died during childbirth in April.

With no club willing or able to offer him one last crack at the Champions League, he's chosen a different, financially lucrative route. It appears Father Time has even caught up with Cristiano Ronaldo, who turns 38 in February.

There is no shame in leaving Europe, many past legends have made similar moves late in their career, such as Pele, Johann Cruyff, Xavi and Andreas Iniesta. And if it's the last time we see him at the top level of club football, he farewells the continent having won every accolade on offer.

Together with Lionel Messi he redefined modern football and his achievements on the football pitch will reverberate around football circles for decades to come.