This name was borne by the heroine of Lewis Carroll's novels Alice's Adventures in Wonderland (1865) and Through the Looking Glass (1871).
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 was popular throughout the English-speaking world in the early 20th century. It staged a comeback in the early 21st century, returning to the American top ten in 2017.
This spelling was used by Lord Byron for characters in The Giaour (1813) and Don Juan (1819), and it is through him that the name was introduced to the English-speaking world.
It has occasionally been used as an English given name since the 16th century. It was moderately popular in the 1940s, but had a more notable upswing in the early 2000s. This may have been inspired by the Spanish actress Penélope Cruz (1974-), who gained prominence in English-language movies at that time. It was already rapidly rising when celebrities Kourtney Kardashian and Scott Disick gave it to their baby daughter in 2012.