Short answers, pulled from the story.
Tantalus was a mythological figure and son of Zeus who may be based on real rulers of Anatolia. Some scholars suggest the name derives from Hantili, one of two Hittite kings who governed regions near Mount Sipylus.
Pausanias reported that ruins of this city were still visible by the beginning of the Common Era. Few traces remain today despite these ancient observations.
Zeus placed a giant rock above Tantalus's head to threaten him if he moved too close while water receded before he could drink. This eternal torment appears in fragments from Archilochus, Alcman, Alcaeus, and Pherecydes.
Tantalus had several children including Pelops, Niobe, Broteas, and sometimes Dascylus. Through Pelops, he became the progenitor of the House of Atreus named after his grandson Atreus.
The earliest reference to this version comes from Pindar’s Olympian Ode 1 written around 476 BCE. In it Clotho one of the Fates revives Pelops in a cauldron after being eaten replacing his shoulder with ivory.