Geoffrey based parts of Merlin's character on Myrddin Wyllt, a legendary madman and prophet who lived in the Caledonian Forest. Other parts of his life were based on that of the historical 5th-century Romano-British military leader Ambrosius Aurelianus (also known as Emrys Wledig). In Geoffrey's version of the tales and later embellishments Merlin is a magician and counselor for King Arthur.
The name was introduced to the English-speaking world by E. D. E. N. Southworth's novel Gloria (1891) and George Bernard Shaw's play You Never Can Tell (1898), which both feature characters with a Portuguese background [1]. It was popularized in the early 20th century by American actress Gloria Swanson (1899-1983). Another famous bearer is feminist Gloria Steinem (1934-).