Sir David Brewster KH PRSE FRS FSA Scot FSSA MICE was a British scientist, inventor, author, and academic administrator. In science he is principally remembered for his experimental work in physical optics, mostly concerned with the study of the polarization of light and including the discovery of Brewster's angle. He studied the birefringence of crystals under compression and discovered photoelasticity, thereby creating the field of optical mineralogy. For this work, William Whewell dubbed him the "father of modern experimental optics" and "the Johannes Kepler of optics."

The Royal Guelphic Order, sometimes referred to as the Hanoverian Guelphic Order, is a Hanoverian order of chivalry instituted on 28 April 1815 by the Prince Regent. It takes its name from the House of Guelph, of which the Hanoverians were a branch. Since Hanover and the United Kingdom shared a monarch until 1837, the order was frequently bestowed upon British subjects.