Why did Horace Mann believe religion should not be taught in school?

Horace Mann believed that religion should not be taught in schools to ensure the separation of church and state and to promote a common, secular education for all students, regardless of their religious backgrounds. He argued that public education should focus on civic virtues and moral values that could unite a diverse population, rather than potentially dividing it along religious lines. Mann advocated for a system that emphasized critical thinking and universal principles rather than specific religious doctrines. This approach aimed to foster social harmony and inclusivity in a pluralistic society.