Canis Major
Canis Major is a prominent constellation because of its many bright stars. These include Sirius (Alpha Canis Majoris), the brightest star in the night sky, as well as three other stars above magnitude 2.0. Furthermore, two other stars are thought to have previously outshone all others in the night sky—Adhara (Epsilon Canis Majoris) shone at -3.99 around 4.7 million years ago, and Mirzam (Beta Canis Majoris) peaked at −3.65 around 4.42 million years ago. Another, NR Canis Majoris, will be brightest at magnitude −0.88 in about 2.87 million years' time.
Royal stars
The four dominant stars have an apparent magnitude–1.5 or brighter. The reason why they are called "Royal" is that they appear to stand aside from the other stars in the sky. The four stars, Aldebaran, Regulus, Antares, Fomalhaut, are the brightest stars in their constellations and among the 25–brightest stars in the night sky. The Persians considered these stars to be the four guardians of the heavens. They marked the seasonal changes and marked the equinoxes and solstices.