In the Biblical apocrypha references to angelic Grigori appear in the books of Enoch and Jubilees. According to the Book of Enoch, the Grigori numbered a total of 200 but only their leaders are named:
A different idea of the Grigori appears in some traditions of Italian witchcraft where the Grigori are said to come from ancient stellar lore.
The "watchers" story in Enoch appears to be derived from Genesis where it describes the "Origin of the Nephilim" and mentions the "Sons of God" who beget them:
Here, the "sons of God" are given no specific name or function; they could represent fallen angels, or simply heavenly beings that mate with women.
The Book of Jubilees adds further details about the "watchers".
In the Book of Daniel an Aramaic term used to denote angels is "watchers" (`îrîn). Each of these heavenly beings is called by the double name "watcher and holy one" (`îr weqadîsh), which denotes one type of heavenly being not two. The term "watcher" probably derives from the verb "to be awake" or "to be vigilant," so that the implication of calling the angels "watchers" is that they are constantly on watch as sentinels for Yahweh.
Angels were fairly popular in Jewish folklore, which often describes them as looking like large human beings that never sleep and remain forever silent. While there are good and bad "watchers", most stories revolve around the evil ones that fell from grace when they took "the daughters of man" as their mates.
In the early stellar cults of Mesopotamia there were four "royal" Stars (known as Lords) which were called the "watchers". Each one of these stars "ruled" over one of the four cardinal points common to Astrology. This particular system would date from approximately 3000 BC. The star Aldebaran, when it marked the Vernal Equinox, held the position of Watcher of the East. Regulus, marking the Summer Solstice, was Watcher of the South. Antares, marking the Autumn Equinox, was Watcher of the West. Fomalhaut, marking the Winter Solstice, was Watcher of the North. In the star myths the "watchers" themselves were depicted as gods who guarded the Heavens and the Earth. Their nature, as well as their "rank", was altered by the successive lunar and solar cults that replaced the older stellar cults.
Earlier mystical Hebrew sects organized the "watchers" into an archangel hierarchy. According to this system the "watchers" were ruled over by four great "watchers" known as Michael, Gabriel, Raphael, and Auriel. In the Old Testament there is reference made to the Irin, or "watchers", which appear to be an order of angels. In early Hebrew lore the Irin were a high order of angels that sat on the supreme Judgment Council of the Heavenly Court. In the Apocryphal Books of Enoch and Jubilees, the "watchers" were sent to Earth to teach law and justice to humankind. The most common associations found in various texts on Medieval magic regarding the "watchers" are as follows:
It is these same angels who are referred to as the Benei Ha-Elohim (Eng. Sons of God) in the Book of Genesis. According to Christian belief their sins filled the Earth with violence and the world was destroyed as a result of their intervention. Richard Cavendish, in his book The Powers of Evil, makes references to the possibilities of the Giants mentioned in Genesis 6:4, being the Giants or Titans of Greek Mythology. He also lists the "watchers" as the fallen angels which magicians call forth in ceremonial magic. Cavendish mentions that the "watchers" were so named because they were stars, the "eyes of night."
Eventually the Greeks reduced the "watchers" to the gods of the four winds. Christian theologians joined the "watchers" to an evil class of fallen angels known as the principalities of the air. St. Paul, in the New Testament, calls the Fallen Angels "principalities": "for we are not contending against flesh and blood, but against the principalities, against the powers...against the spiritual hosts of wickedness in High Places". It was also St. Paul who called Satan "The prince of power of the air", and thus made the connection of Satan (himself connected to "a star", Isiah 14: 12 14) and etheric beings, for they were later known as demons and as principalities of the Air.
This theme was later developed by a French theologian of the 16th Century, named Sinistrari, who referred to the Watchers as beings existing between Humans and Angels. He called them demons and associated them with the Elemental natures of Earth, Air, Fire and Water. This, however, was not a new concept but was taught by certain Gnostic sects in the early days of Christianity. Clement of Alexandria, influenced by Hellenistic cosmology, attributed the movement of the Stars and the control of the four elements to angelic beings. Sinistrari attributed bodies of fire, air, earth, and water to these Beings, and concluded that the "watchers" were made of fire and air. Cardinal Newman, writing in the mid 1800s, proposed that certain angels existed who were neither totally good nor evil, and had only "partially fallen" from the Heavens.
Some Italian witches believe that Charles Leland's book Aradia, or the Gospel of the Witches preserves a tradition around the Grigori, who they believe appear as "the great spirits of the stars" in the legend "The Children of Diana, or how the fairies were born" and as "the fathers of the Beginning, [...] the mothers, the spirits who were before the first spirit" in the legend "How Diana made the Stars and the Rain".