1. Mithraicism was a mystery cult that flourished in the Roman Empire from the 1st to the 4th century CE.
（米特拉教是一个在公元1-4世纪在罗马帝国盛行的神秘教派。）
2. The followers of Mithraicism held secret ceremonies in underground temples known as Mithraea.
（米特拉教的信徒在地下神庙中进行秘密仪式，这些神庙称为米特拉斯。）