Ancient Greek and Roman Religion
The hellenistic religion of ancient Greek and Rome was polytheistic. Hundreds of divine beings interfered with the lives of people. Some were extremely powerful like Zeus/Jupiter, others only had very minor roles. They helped humans they liked and created a lot of problems to those they didn't like. It was therefore crucially important to respect them, perform their rites correctly, offer sacrifices, promise rewards in exchange for their favour and keep all such promises.