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The letter is a look back at Ronaldinho's storied career which included winning the World Cup in 2002 and winning the Ballon d'Or in 2005 as the world's top footballer.
He also writes about growing up in a rough section of Porto Alegre in Brazil. It was there that Ronaldinho first began to hone his skills and that his dog had a lot to do with it.
You see, people get tired, but according to Ronaldinho, Bombom was "a tireless defender."
"Where you live in Porto Alegre, there are drugs and gangs and that kind of stuff around. It's going to be tough, but as long as you are playing football - on the street, at the park, with your dog - you will feel safe.
Yes, I said your dog, by the way. He's a tireless defender.
You'll play with [your older brother] Roberto. You'll play with other kids and older guys at the park. But eventually everyone will get tired - and you will want to keep playing. So make sure you always take your dog, Bombom, out with you. Bombom is a mutt. A real Brazilian dog. And even Brazilian dogs love football. He'll be great practice for dribbling and skills … and maybe the first casualty of the "Elastico."
Years from now, when you are playing in Europe, a few defenders will remind you of Bombom."
For those not familiar, the "elastico" - which is also called the "flip flap" - refers to Ronaldinho's signature dribbling move in which he would fake one way and then pull the ball back as if it were attached to a rubber band. By the time the defender knew what happened, Ronaldinho was gone in the other direction.