Question

Why is secular literature an important source of history

Answer 1

Secular is the opposite of sacred. Note: Secularization refers to the declining influence of religion and religious values within a given culture. Secular humanism means, loosely, a belief in human self-sufficiency.

Answer 2

Secular literature is an important source of history because the secular sources help us to collaborate with other sources and scrutinize the facts.

The secular literature contains detailed information about all aspects of state and  society- political, socio-economic, laws and rules. These sources give us information about the dynasties and kings of the time. More importantly these sources don't contain myths like the religious literature.