Nimbus
The nimbus is the bright circle on the subject`s head, already in use among the Egyptians, Romans and Greeks to represent their gods. In the second century A.C. it appears also in Roman emperors’ portraits, to represent their divine origin. In Christian art the nimbus was used in Christ`s images (in this case it carries a cross and for this reason it is called "nimbus crucifer"), and later it was used in pictures of angels, evangelists and apostles. Since the seventh century it has been attributed to all the saints.