The New Student's Reference Work/Polestar

Pole′star or Pola′ris, the star nearest to the northern pole of the celestial quarter.  The star which at present goes under the name of the polestar is Alpha in the constellation of Ursa Minor.  This star, however, is a little more than 1° from the north pole and has a sensible motion around it.  This star will in about 2,100 A. D. come within 28′ of the north pole of the heavens, and then recede.  Two thousand years ago Beta of Ursa Minor was the polestar, and about 2,300 B. C. Alpha in the constellation of the Dragon was not more than 10′ from the north pole, while 12,000 years after the present time the bright star Vega in Lyra will be within 5° of it.