In many cultures and contexts, earrings have traditionally been worn as symbols of cultural or tribal identity, as markers of age, marital status, or rank, or because they are believed to have protective or medicinal powers. Even when they have served other purposes, however, the primary function of earrings has been a decorative one. The crescent-shaped gold hoops worn by Sumerian women around 2500 b.c.e. are the earliest earrings for which there is archaeological evidence. By 1000 b.c.e., tapered hoop (also known as boat-shaped) earrings, most commonly of gold but also of silver and bronze, had spread throughout the Aegean world and Western Asia.