remusjohnslupin:

Haladin were probably more numerous than the Folk of Bëor, but no certain count of them was ever made. The Folk of Haleth were strangers to the other Atani, speaking an alien language; and though later united with them in alliance with the Eldar, they remained a people apart. One of the strange practices spoken of was that many of their warriors were women, though few of these went abroad to fight in the great battles. This custom was evidently ancient (not due to their special situation in Beleriand), and maybe rather a cause of their small numbers than its result. They increased in numbers far more slowly than the other Atani, hardly more than was sufficient to replace the wastage of war; yet many of their women (who were fewer than the men) remained unwed; for their chieftainess Haleth had been a renowned amazon with a picked bodyguard of women.