The bright stars in Crux were known to the Ancient Greeks, where Ptolemy regarded them as part of the constellation Centaurus. They were entirely visible as far north as Britain in the fourth millennium BC. However, the precession of the equinoxes gradually lowered the stars below the European horizon, and they were eventually forgotten by the inhabitants of northern latitudes. By 400 CE, the stars in the constellation we now call Crux never rose above the horizon throughout most of Europe. Dante may have known about the constellation in the 14th century, as he describes an asterism of four bright stars in the southern sky in his "Divine Comedy". His description, however, may be allegorical, and the similarity to the constellation a coincidence.