Simplify the following text for a Grade 10 native English-speaking person.
Original: Former Williams driver Nico Rosberg was joined by seven-time World Champion Michael Schumacher for the team 's maiden racing season , and both have retained their seats for the 2011 season .
Simplified: Former Williams driver Nico Rosberg was joined by seven-time World Champion Michael Schumacher for the team 's maiden racing season .