古風時期
Most extant material about Thetis concerns her role as mother of Achilles, but there is some evidence that as the sea-goddess she played a more central role in the religious beliefs and practices of Archaic Greece. The pre-modern etymology of her name, from "tithemi" (τίθημι), "to set up, establish," suggests a perception among Classical Greeks of an early political role. Walter Burkert considers her name a transformed doublet of Tethys.