The ancient Greek mythical hero Achilles was born in the Fthia region (Phthiotis) of Thessaly. His father, Peleus, was the ruler of the Myrmidons, a warrior people of this region, which extended from Nea Anchialos to Farsala. Achilles' mother, Thetis, was a Nereid.
From the time of his birth, Thetis wished to make Achilles immortal. To do this, she burned him nightly over a fire, applying ambrosia to the resulting wounds. She also, more famously, lowered him into the River Styx, keeping hold of him by his ankle. While Thetis was successful in this latter approach to conferring invulnerability upon her son, the waters of the Styx did not come into contact with his ankle, so he was left vulnerable in this area. She was also seen apparently trying to drown her son by Peleus, who exiled her for the deed.
Much of Achilles' childhood was engaged in training to be a warrior and hunter, as well as learning the arts of medicine and music, under the tutorship of the centaur Chiron. This period was intended by his father as preparation for Achilles' involvement in the Trojan war. His mother remained protective over her son, attempting to spare Achilles' life by hiding him on the island of Skyros in the Aegean Sea when he was 9 years old.