A guardian angel is a type of angel that is assigned to protect and guide a particular person, group or nation. Belief in tutelary beings can be traced throughout all antiquity. The idea of angels that guard over people played a major role in Ancient Judaism. In Christianity, the hierarchy of angels was extensively developed in the 5th century by Pseudo-Dionysius the Areopagite. The theology of angels and tutelary spirits has undergone many changes since the 5th century. The belief is that guardian angels serve to protect whichever person God assigns them to. The idea of a guardian angel is central to the 15th-century book The Book of the Sacred Magic of Abramelin the Mage by Abraham of Worms, a German Cabalist. In 1897, this book was translated into English by Samuel Liddell MacGregor Mathers (1854–1918), a co-founder of the Hermetic Order of the Golden Dawn, who styled the guardian angel as the Holy Guardian Angel. Aleister Crowley (1875–1947), the founder of the esoteric religion Thelema, considered the Holy Guardian Angel to be representative of one's truest divine nature and the equivalent of the "Genius" of the Hermetic Order of the Golden Dawn, the Augoeides of Iamblichus, the Atman of Hinduism, and the Daimon of the ancient Greeks. Following the teachings of the Golden Dawn, Crowley refined their rituals which were intended to facilitate the ability to establish contact with one's guardian angel. Fravashi Also known as Arda Fravaš ('Holy Guardian Angels'). Each person is accompanied by a guardian angel, which acts as a guide throughout life. They originally patrolled the boundaries of the ramparts of heaven, but volunteer to descend to earth to stand by individuals to the end of their days. The guardian angel concept is present in the books of the Hebrew Bible, and its development is well marked. These books described God's angels as his ministers who carried out his behests, and who were at times given special commissions, regarding men and mundane affairs.