Simplify the following text for a Grade 10 native English-speaking person.
Original: On 3 March 2011 , because of Karl-Theodor zu Guttenberg 's resignation , de MaiziÃ re became Federal Minister for Defense .
Simplified: On March 2 , 2011 , Chancellor Merkel announced that MaiziÃ re would be the successor of Federal Minister of Defense zu Guttenberg , who had resigned from office the previous day . On 3 March 2011 he was appointed .