Simplify the following text for a Grade 15 native English-speaking person.
Original: He traveled to San Diego and on March 5 , 2005 , as part of the University of San Diego 's Kyoto Symposium , gave a speech entitled The Public Role of Religion in Secular Context , regarding the evolution of separation of Church and State from neutrality to intense secularism .
Simplified: He traveled to San Diego and on March 5 , 2005 , as part of the University of San Diego 's Kyoto Symposium , gave a speech entitled The Public Role of Religion in Secular Context , regarding the history of separation of Church and State .