noun
religious war
A war primarily motivated by religious differences or goals.
ヨーロッパでは宗教戦争が何度も起こった。
Religious wars broke out many times in Europe.
聖戦 (holy war) is a war sanctioned by a religious authority, while 宗教戦争 is a broader term for any war driven by religious causes.
Compound of 宗教 (religion) and 戦争 (war).