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.
The popularity of the name Eleanor in England during the Middle Ages was due to the fame of Eleanor of Aquitaine, as well as two queens of the following century: Eleanor of Provence, the wife of Henry III, and Eleanor of Castile, the wife of Edward I. More recently, it was borne by first lady Eleanor Roosevelt (1884-1962), the wife of American president Franklin Roosevelt.
This name has been used occasionally in England since the 12th century. It was not common in the English-speaking world until the end of the 20th century.
This was a common name in classical Greece, and, due to both the saints who carried it and the favourable meaning, it came into general use in the Christian world, being especially popular among Eastern Christians. It was however rare in Britain before the 19th century. Famous bearers include three tsars of Russia (in the Russian form Fyodor) and American president Theodore Roosevelt (1858-1919).