eminence (n.) Look up eminence at Dictionary.com
c.1400, "projection, protuberance;" early 15c., "high or exalted position," from Old French eminence or directly from Latin eminentia "prominence, eminence," from eminentem (nominative eminens) "excellent, prominent" (see eminent).

As a title of honor (now only of cardinals) it is attested from 1650s. The original Éminence grise (French, literally "gray eminence") was François Leclerc du Trembley (1577-1638), confidential agent of Richelieu.