Here is poem about evil spirits of ancient Sumer. May be that's where it all started.
Quote:DESCRIPTIONS OF "THE SEVEN"
I
Destructive storms and evil winds are they,
A storm of evil, presaging the baneful storm,
A storm of evil, forerunner of the baneful storm.
Mighty children, mightv sons are they,
Messengers of Namtar are they,
Throne-bearers of Ereshkigal. [1]
The flood driving through the land are they.
Seven gods of the wide heavens,
Seven gods of the broad earth,
Seven robber-gods are they.
Seven gods of universal sway,
Seven evil gods,
Seven evil demons,
Seven evil and violent demons,
Seven in heaven, seven on earth.
II
Neither male nor female are they.
Destructive whirlwinds they,
Having neither wife nor offspring.
Compassion and mercy they do not know.
Prayer and supplication they do not hear.
Horses reared in the mountains, Hostile to Ea.
Throne-bearers of the gods are they.
Standing on the highway, befouling the street. Evil are they, evil are they,
Seven they are, seven they are, Twice seven they are.
III
The high enclosures, the broad enclosures like a flood they pass through.
From house to house they dash along.
No door can shut them out,
No bolt can turn them back.
Through the door, like a snake, they glide,
Through the hinge, like the wind, they storm.
Tearing the wife from the embrace of the man,
Snatching the child from the knees of a man,
Driving the freedman from his family home.