According to Wikipedia, the three decided to launch the company after winning a mobile game development contest with a "real-time multiplayer game called King of the Cabbage World." They called their startup Relude and eventually sold King of the Cabbage World to another company, which renamed it Mole War.
Wikipedia says Mole War became "the first commercial real-time multiplayer mobile game in the world."
In 2009, Hed, Väkeväinen and Dikert -- still working under the company name Relude -- released the game Angry Birds. They changed the company's name to Rovio Entertainment Ltd. in July 2011.
Today, Rovio is led by Mikael Hed (CEO), Niklas Hed (chief operating officer) and Peter Vesterbacka, who's described at the company's chief marketing officer and "Mighty Eagle."