In Britain the parallel form Alice, derived via Old French, has historically been more common than Adelaide, though this form did gain some currency in the 19th century due to the popularity of the German-born wife of King William IV, for whom the city of Adelaide in Australia was named in 1836.
Due to the popularity of the saint, the name became common in the Christian world during the Middle Ages. The Normans brought it to England, where it was commonly spelled Cecily — the Latinate form Cecilia came into use in the 18th century.
Due to its favourable meaning, this name was popular among early Christians, being borne by many early saints and four popes. It has been used in England since the Middle Ages, though it has been more popular in continental Europe. A notable bearer was the German composer Felix Mendelssohn (1809-1847).
The name has been very common throughout the English-speaking world since end of the 20th century. In the United States it reached a high point in 2017, when it ranked as the fifth most popular name for boys.
Its modern use as a feminine name may have been influenced by the British-American author Taylor Caldwell (1900-1985). Since 1990 it has been more popular for girls in the United States. Other England-speaking regions have followed suit, with the exception of England and Wales where it is still slightly more popular for boys. Its popularity peaked in America the mid-1990s for both genders, ranked sixth for girls and 51st for boys. A famous bearer is the American musician Taylor Swift (1989-).