Seventh heaven/

Describing a moment of bliss to a friend I said I was in '7th Heaven'. Does anyone know how this term came about? Given there's only one heaven in Christian terms, I assume it's not Christian based - although I obviously don't actually know.

Here ya go, Goddess,
seventh heaven
(Islam, Religion)
n.
1. A state of great joy and satisfaction.
2. The farthest of the concentric spheres containing the stars and constituting the dwelling place of God and the angels in the Muslim and cabalist systems.

The American Heritage® Dictionary of the English Language, Fourth Edition. Copyright © 2003 by Houghton Mifflin Company