Its source is Atalante, a Greek name meaning "Secure."
In Greek mythology, Atalante (or Atalanta) was a huntress of legendary power, and one of the Argonauts.
She was especially known for her swiftness, and she challenged the heroes around her to race. If the man won, he could marry her. If she won, she could dispose of the loser's life.
Many attempted to defeat her, only to fail and suffer death at her hands. Eventually a Greek warrior (either Meilanion or Hippomenes, depending on the version of the tale) defeated her with a cunning stratagem. As he ran, he dropped three golden apples he had obtained from the goddess Aphrodite. The huntress paused to pick them up, he finished ahead of her, and she was his.