Crasis for 'kaloi kai agathoi', which is the
Greek for 'beautiful and good ones'.
This was the name the ancient Greek Aristocrats called themselves. Through this they wanted to express their claim to rule the various poleis. The assumption was that they, being 'those born to good fathers' (eupatridai), were better than the rest of the population morally as well as in their skills and talents, and therefore were those meant to lead. They referred to the members of the lower classes as 'kakoi', or 'bad ones'.
This perception of the connection between excellence, morals and class dates back to Homer, and in the Iliad in particular one can see how excellence is often a direct derivation of class. This way, Agamemnon can win a lance-throwing contest without even lifting the lance, and a commoner who opposes Agamemnon's wishes, is referred to as ugly and foolish. In addition for many years, and until the classical period itself the word 'agathos' means both 'a member of a higher class' and 'morally good'.
This tendency intensified as Greece entered the Archaeic era (cf. polis), the aristocracy became the ruling class of most of the Greek poleis, and monarchy dwindled, and remained prevalent in the writings of many anti-democratic rhetoricians, philosophers, historians and other scholars.