mid-14c., nobilite, "honor, renown; majesty, grandeur;" late 14c., "quality of being excellent or rare," from Old French nobilite "high rank; dignity, grace; great deed" (12c., Modern French nobilité), and directly from Latin nobilitatem (nominative nobilitas) "celebrity, fame; high birth; excellence, superiority; the nobles," from nobilis "well-known, prominent" (see noble (adj.)).
Meaning "quality of being of noble rank or birth; social or political preeminence, usually accompanied by hereditary privilege" is attested from late 14c.; sense of "the noble class collectively" is from late 14c. Sense of "dignity of mind, elevation of the soul, loftiness of tone" is from 1590s.