Although this is a grammatically masculine adjective in French, it is given to girls as well as boys in Britain and the Netherlands. In America it is more exclusively masculine. It is not commonly used as a name in France itself.
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.
As a given name, Diana has been regularly used since the Renaissance. It became more common in the English-speaking world following Walter Scott's novel Rob Roy (1817), which featured a character named Diana Vernon. It also appeared in George Meredith's novel Diana of the Crossways (1885). A notable bearer was the British royal Diana Spencer (1961-1997), the Princess of Wales.