Simplify the following text for a Grade 14 native English-speaking person.
Original: The foundation stone was placed by Hazrat Mirza Tahir Ahmad on the 19 October 1999 , in a ceremony attended by 2000 guests , and inaugurated by the current head of the Ahmadiyya Muslim Community , Hazrat Mirza Masroor Ahmad , on the 3 October 2003 .
Simplified: The foundation stone was placed by Hazrat Mirza Tahir Ahmad on the 19 October 1999 , in a ceremony attended by 2000 guests , and opened by the current head of the Ahmadiyya Muslim Community , Hazrat Mirza Masroor Ahmad , on the 3 October 2003 .