Simplify the following text for a Grade 10 native English-speaking person.
Original: They held a religious ceremony at the Basilica Cathedral in Lima on April 5 , 2008 , which some of Peru 's greatest celebrities , including President Alan GarcÃ a and author Mario Vargas Llosa , attended .
Simplified: They held a religious ceremony at the Basilica Cathedral in Lima on April 5 , 2008 . Some of Peru 's most famous people went , including President Alan GarcÃ a and author Mario Vargas-Llosa .