Note for Actual Portuguese speakers: I am very very sorry for butchering your language. It was a moment of weakness.
Done for a contest on AlternateHistory.com, but I turned it in too late. Here it is now.
Basically, it's a union of mostly former-Portugese Colonies (some Dutch, English and Native States) created in the 19th century to increase the power against an expansionist state from Central-West Europe. Now the largest state in the World. Forgot the rest of the story, sorry.