North Star

Polaris, the brightest star in Ursa Minor, sits nearly on Earth's rotational axis, causing all northern stars to appear to revolve around it. Ancient navigators used the constellation for orientation as early as classical antiquity, though Polaris itself became the dominant pole star only in the medieval period as axial precession shifted it closer to true north. Its metaphorical use as a fixed guiding reference has been common in English since at least the 19th century.