Zeus, Hera, Poseidon, Demeter, Ares, Hermes, Hephaestus, Aphrodite, Athena, Apollo, and Artemis are always considered to be Olympians. Hestia, Dionysus, and Hades are the gods who have sometimes been Olympians. Thus, it is theorized that Hestia gave up her place to Dionysus because she wanted to live amongst humans however no records of this actually exist