The sun orbits Sirius, and is currently close to the aphelion, the furthest the two stars get from one another (actually, roughly 2000 years has passed since the aphelion when Sirius also changed color from red shift to blue shift, and a "star was born in Betlehem"), and around 15,000 years ago the sun was very close to Sirius, so Sirius was very big in the sky, and the ancient society therefore knew about the sun-Sirius system because it was quite clear that the big red star that was much much bigger than other stars, was related to the long long months of 2000 years that had a precession of the same constellations as the 30-or-so day long months, the Earth orbits the sun in the same plane as the sun orbits Sirius.
That the Earth's magnetic field reversed around 12000 years ago is well known from records of how the Earth prior to the pole shift had glaciation on the northern hemisphere rather than the southern hemisphere, Antarctica was largely ice free since the magnetic field that was the reverse of what you have today forced water into a solid state on the north pole rather than the south pole, and the melting of the north pole that resulted from the pole switch is widely observable and often described as the "end of the last ice age".
That the magnetic field of the Earth (and therefore of the sun) reversed by 12000 years ago as the sun-Sirius system had distanced itself from the perihelion, the point in the orbital cycle when the two stars are the closest together, by 3000 years, shows that there is a cycle of magnetic reversals in the sun-Sirius system, and I would not be surprised if, was the detail increased in the geological record, by more and more samples and samples taken at more positions in the geological time line, there would turn out to be a pattern of 26000 year cycles, as well as possible larger cycles if there are other orbits besides the sun-Sirius system that has shaped the Earth's magnetic field in the past eons.