The name was mainly confined to Spain and Portugal during the Middle Ages. After the 16th century it was spread to other parts of the Christian world, due to the fame of the Spanish nun and reformer Saint Teresa of Ávila. Another famous bearer was the Austrian Habsburg queen Maria Theresa (1717-1780), who inherited the domains of her father, the Holy Roman emperor Charles VI, beginning the War of the Austrian Succession.
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.
As an English name it has been very popular since the Middle Ages. It was the top name for girls in England and Wales in the 1920s, 30s and 40s, but it declined in the latter half of the 20th century.
Other saints by this name include a queen of Scotland and a princess of Hungary. It was also borne by Queen Margaret I of Denmark, who united Denmark, Sweden, and Norway in the 14th century. Famous literary bearers include American writer Margaret Mitchell (1900-1949), the author of Gone with the Wind, and Canadian writer Margaret Atwood (1939-). Others include American anthropologist Margaret Mead (1901-1978) and British prime minister Margaret Thatcher (1925-2013).
This name has traditionally been more popular among Eastern Christians. In the English-speaking world it was not regularly used until the 19th century.
Among Christians, this name was originally more common in Eastern Europe. It was borne in the 12th century by Saint Elizabeth of Hungary, a daughter of King Andrew II who used her wealth to help the poor. In medieval England it was occasionally used in honour of the saint, though the form Isabel (from Occitan and Spanish) was more common. It has been very popular in England since the reign of Queen Elizabeth I in the 16th century. In American name statistics (as recorded since 1880) it has never ranked lower than 30, making it the most consistently popular name for girls in the United States.
Besides Elizabeth I, this name has been borne (in various spellings) by many other European royals, including a ruling empress of Russia in the 18th century. Famous modern bearers include the British queen Elizabeth II (1926-2022) and actress Elizabeth Taylor (1932-2011).
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.