Rambam, Guide of the Perplexed 3:54
The fourth species is the true human perfection; it consists in the acquisition of the rational virtues—I refer to the conception of intelligibles, which teach true opinions concerning the divine things. This is the true reality the ultimate end; this is what gives the individual true perfection, a perfection belonging to him alone; and it gives him permanent perdurance; through it man is man.
Time Period: Medieval (Geonim through the 16th Century)