As a given name it was mostly masculine before 1940, but it rose in popularity as a name for girls during the 40s and 50s, probably due both to Grace Kelly (who married Prince Rainier III of Monaco in 1956) and a female character on the 1957 television series Bachelor Father [1]. By the end of the 1970s it was on the decline.
This name has been borne by two kings of the Franks, two dukes of Normandy, and three kings of Scotland, including Robert the Bruce who restored the independence of Scotland from England in the 14th century. Several saints have also had the name, the earliest known as Saint Rupert, from an Old German variant. The author Robert Browning (1812-1889) and poets Robert Burns (1759-1796) and Robert Frost (1874-1963) are famous literary namesakes. Other bearers include Robert E. Lee (1807-1870), the commander of the Confederate army during the American Civil War, and American actors Robert Redford (1936-), Robert De Niro (1943-) and Robert Downey Jr. (1965-).
In the United States this name steadily grew in popularity through the 1950s and 60s. It shot up the charts after the release of the 1970 movie Ryan's Daughter. Within a few years it was in the top 20 names, where it would stay for over three decades. Famous bearers include the Canadian actors Ryan Reynolds (1976-) and Ryan Gosling (1980-).
This also coincides with an Irish surname (an Anglicized form of Irish Gaelic Mac Searraigh), derived from the byname Searrach meaning "foal".