Phaedrus

But souls which fall behind and lose their vision of the truth, and are for some unfortunate reason or another weighed down by being filled with forgetfulness and weakness, lose their wings thanks to this burden and fall to earth. At this point they are subject to a law that they are not to be planted into the bodies of animals in their first incarnation. The souls which have seen the most are to enter the seeds of men who will become philosophers, lovers of beauty, men of culture, men who are dedicated to love; the second group those of law-abiding kings or military commanders or civic leaders; the third group those of politicians, estate-managers or businessmen; the fourth group those of men who love exercising in a gymnasium or future experts in bodily health; the fifth element will live as prophets or as initiators into one of the mystery cults; the sixth group will most suitably live as poets or some other kind of representative artist, the seventh as artisans or farmer, the eighth as sophists or demagogues, and the ninth as tyrants.