By the third century BC the Greeks had begun to use the Little Bear, Ursa Minor, to navigate. In the mid-1st century AD Lucan writes of Pompey who questions a sailor about the use of stars in navigation. The sailor replies with his description of the use of circumpolar stars to navigate by. To navigate along a degree of latitude a sailor would have needed to find a circumpolar star above that degree in the sky. For example, Apollonius would have used β Draconis to navigate as he traveled west from the mouth of the Alpheus River to Syracuse.