Answer:
The main cause of English Civil war was Religion.
Step-by-step explanation:
English Civil war was the conflict between Roman Catholicism and Protestantism. It was fought between Parliament , who wanted to limit the power of kings and the kings, who were from Stuart dynasty and Catholics who were linked to Rome.
"King Charles I" had married the Roman Catholic “Henrietta Maria” in the beginning of his rule. He was defeated and executed in 1649. Republic had returned but it did not work, and Monarchy was again introduced. Restoration period ended when the last king of Stuart dynasty was expelled and never returned to the throne.