Unspecified period before the events of Genesis 6:1-4: Mesopotamian belief systems describe the apkallu, seven mythological sages associated with the god Ea, who lived before the Flood and possessed wisdom and secret knowledge. These apkallu could be depicted as either benevolent or malevolent. Figurines of apkallu, referred to as maṣṣarē ("watchers") in Akkadian incantations, were buried as foundation deposits to avert evil.
Unspecified period after creation: Some Second Temple texts attribute the cause of human sin to demonic forces.
Unspecified period before the Flood: Some texts locate the sin impulse within human nature itself, independent of external forces.
In the days of Jared (before the Flood): Two hundred Watchers, described as "sons of heaven" and "sons of God," descend to the peak of Mount Hermon. Their chief is Shemihazah.
On Mount Hermon (in the days of Jared): The Watchers swear an oath and bind themselves with a curse to choose wives from the daughters of men and beget children. They name the mountain "Hermon" because of this sworn oath.
After the Watchers descend to Earth: The Watchers engage in unlawful unions with the daughters of men. These unions produce the Nephilim, also referred to as giants and an "infamous race of men."
After the Watchers descend to Earth: Asael teaches men how to make swords, weapons, shields, breastplates, and other instruments of war from metals. He also teaches them how to work gold and silver for ornaments and how to use antimony, eye paint, precious stones, and dyes for beautification.
After the Watchers descend to Earth: Shemihazah teaches spells and the cutting of roots (likely referring to sorcery and illicit knowledge).
During the time of the Watchers' activities: Much godlessness exists upon the earth, and the ways of men are made desolate.
During the time of the Watchers' activities: The earth becomes corrupted by the sexual union of the Watchers with women and the illicit knowledge they share.
Before the Flood: God sends Sariel to Noah, the son of Lamech, to warn him of the coming Flood that will destroy everything on earth. Noah is instructed on how to preserve himself and his seed.
During or after the death of the giants (offspring of the Watchers): The spirits of the giants, who inherited the wicked nature of their Watcher fathers, go forth from their dead bodies. These spirits are called evil spirits and demons.
From the day of the slaughter of the giants until the final judgment: The spirits of the giants make desolate and wreak havoc on the human race. They are described as leading astray, doing violence, making desolate, attacking, wrestling, hurling upon the earth, causing illnesses, and striking unexpectedly to lead the spirit of understanding astray. They abstain from food and are thirsty and smite.
Throughout the period of the spirits of the giants' activity: These evil spirits will be on the earth and will rise up against the sons of men and women because they came forth from them. They act without incurring immediate judgment and will continue their activities until the consummation of the great judgment.
After the Flood: Some Second Temple Period material, such as the Dead Sea Scroll 4Q 510 (4QShira), includes the post-Flood Watchers ("bastard spirits") in its indictment of evil forces.
After the Flood: According to the Babylonian version of the Flood story, the god Marduk confines the apkallu who cohabited with humans to Apsu and prevents their access to the mēsu-tree and elmešu-stone.
Second Temple Period: Jewish thought develops the idea of a great eschatological enemy or Antichrist figure based on interpretations of Old Testament passages. This figure is sometimes conceived as Satan (Beliar) incarnate or as an embodied Watcher-spirit in league with Satan.