The hunting goddess

Diana had a number of attributes which characterised her as a huntress. Unlike the women of Antiquity she did not wear an ankle-length robe, but a short tunic, tied at the waist, which fell to just above the knee. This was the outfit worn by people who required liberty of movement (hunters, craftsmen, sometimes gladiators).
Her hairstyle was also adapted to her hunting activities: she wore a chignon at the top of her head, which kept her hair out of her eyes. Her final hunting attribute was the quiver, visible here behind her right shoulder. She must once have held a bow (which is now lost) in her hand, and is portrayed here taking an arrow from her quiver, as if preparing to shoot.
As was usually the case with images of the Roman gods, this portrayal of Diana came from one or more statues that were created in Greece during the classical period. There are also examples in marble, the most famous being the "Diana of Versailles" (now in the Louvre), which portrays the goddess striding forwards, accompanied by a stag, and drawing an arrow from her quiver.