c. 1400, "office or position of a sovereign, royal power or authority," also "magnificence," from or modeled on Old French roialte (12c., Modern French royauté), from Vulgar Latin *regalitatem (nominative *regalitas), from Latin regalis "royal, kingly; of or belonging to a king, worthy of a king" (see royal (adj.)).
The meaning "royal persons collectively" is from late 15c. From the notion of prerogatives of a sovereign the sense expanded to "prerogatives or rights granted by a sovereign to an individual or corporation" (late 15c.). From that evolved more general senses, such as "payment to a landowner for use of a mine" (1839), and ultimately "payment to an author, composer, etc." for sale or use of his or her work (1857). Compare realty.