Task: Question Generation
Input (English): The principal gods of the ancient Greek religion were the Dodekatheon, or the Twelve Gods, who lived on the top of Mount Olympus. The most important of all ancient Greek gods was Zeus, the king of the gods, who was married to Hera, who was also Zeus's sister. The other Greek gods that made up the Twelve Olympians were Demeter, Ares, Poseidon, Athena, Dionysus, Apollo, Artemis, Aphrodite, Hephaestus and Hermes. Apart from these twelve gods, Greeks also had a variety of other mystical beliefs, such as nymphs and other magical creatures.
Output (English): The main gods of ancient Greece known as the what?