From the Hebrew name לֵאָה (Le'ah), which was probably derived from the Hebrew word לְאָה (le'ah) meaning "weary". Alternatively it might be related to Akkadian littu meaning "cow". In the Old Testament Leah is the first wife of Jacob and the mother of seven of his children. Jacob's other wife was Leah's younger sister Rachel, who he preferred. Leah later offered Jacob her handmaid Zilpah in order for him to conceive more children.
Although this name was used by Jews in the Middle Ages, it was not typical as an English Christian name until after the Protestant Reformation, being common among the Puritans.