Cristiano Ronaldo considered quitting football before securing his move to Man United in 2003 as he was being 'bullied' at Sporting Libson, according to reports.
Ronaldo - who was born in February 1985 on the island of Madeira - felt 'lonely and homesick' while plying his trade at the Sporting Lisbon academy.
Ronaldo struggled to fit in with the other kids after moving 535 miles away from his home town in 1997 at just 12 years old.
The information surrounding Ronaldo's difficulties at Sporting was revealed in a book called: Messi vs Ronaldo: One Rivalry, Two GOATs, and the Era That Remade the World's Game.
In extracts published by The Sun, the book claimed that Ronaldo thought about hanging up his boots before his career had even started. He was planning to quit football while in the academy set up in Lisbon.
According to the book, Ronaldo was teased for his heavy Madeiran accent by the other boys and cried every day because he missed his family and local friends.
Ronaldo struggled to control his emotions at such a young age and began lashing out as a result of his circumstances.
The young starlet was said to have been involved in a series of bust-ups and scrapes with other boys in the schoolyard.
Additionally, Ronaldo is said to have thrown a chair at one of his teachers after they made fun of the way he spoke.
As a result of his difficulties at school, Ronaldo was allowed to quit his studies and focus solely on football. He was called up to the Sporting first XI soon after.
Speaking about his relationship with school, Ronaldo once said: 'I always felt that I wasn't cut out for school. So what was the point?'.
Despite dropping out of school and reaching Sporting's first XI, it wasn't until Ronaldo was sold to United for £12million that he started to fall in love with his career.
This is because Sporting prevented Ronaldo from using the gym as he pleased. Therefore, he struggled to bulk up and found himself being knocked off the ball in games.
Sporting had strict policies when it came to 'children' using of the gym. They blocked youngsters from lifting weights and working out regularly as they wanted them to 'grow naturally'.
Academy executive Aurelio Pereira once said: 'We never put children in gyms. That is one of the secrets behind our players' long careers. It's important to let them grow naturally.'
Therefore, Ronaldo - who would tell his team-mates he would be 'the best in the world one day' - would reportedly sneak out of his dormitory at night to lift weights.
Ronaldo's night-time adventures didn't stay secret for long. Once the Sporting coaches found out, he was sentenced to detention.
The club's hierarchy even locked the gym doors with a padlock to prevent the youngster from trying his luck again.
However, this didn't stop Ronaldo from pursuing his goal of getting strong. He decided to get creative and use buckets of water in the shower to perform squats.
Sporting's coaches intervened once again. They reportedly took the buckets away from Ronaldo.
So, he began strapping weights to his ankles and racing cars in his free time to build up his explosive power.
Ronaldo was also caught using the cafeteria's oranges for keepy uppys after the coaches took their balls away from him to prevent him from overdoing training.
When discussing Ronaldo's persistence, Sporting fitness coach Carlos Bruno said: 'He always wanted more. Most players, when the training goes on too long, they say, 'Hey, coach, too much water kills the plant, you know?' Cristiano was a guy who always wanted more water in the plant.'