The Canons of the Council in Trullo; Often Called The Quinisext Council 42Canon XLII.

Those who are called Eremites and are clothed in black robes, and with long hair go about cities and associate with the worldly both men and women and bring odium upon their profession--we decree that if they will receive the habit of other monks and wear their hair cut short, they may be shut up in a monastery and numbered among the brothers; but if they do not choose to do this, they are to be expelled from the cities and forced to live in the desert (eremous) from whence also they derive their name.