This name was common among continental European royalty during the Middle Ages, and it was popularized in Britain by the German House of Hanover when they inherited the British throne in the 18th century. It was the name of characters in the novels Tom Jones (1749) by Henry Fielding and The Vicar of Wakefield (1766) by Oliver Goldsmith.
In the United States this name was only moderately common until the 1990s when it began rising in popularity, eventually becoming the most popular for girls from 2011 to 2013. A famous bearer is the Italian actress Sophia Loren (1934-).
As a Christian name, Ruth has been in use since the Protestant Reformation. In England it was associated with the archaic word ruth meaning "pity, compassion" (now only commonly seen in the word ruthless). The name became very popular in America following the birth of "Baby" Ruth Cleveland (1891-1904), the daughter of President Grover Cleveland.
This name has never been common in the English-speaking world, though it has been well-used elsewhere in Europe. A famous bearer was the Italian Renaissance master Raffaello Sanzio (1483-1520), usually known simply as Raphael in English.
Due to the renown of the saint, this name has been widely used in the Christian world. It has been common in England since the 12th century, though it became a bit less popular after the Protestant Reformation. The name has been borne by five popes and two tsars of Russia.
Already an uncommon masculine name, it slowly grew in popularity for American girls beginning in 1978 after the start of the sitcom WKRP in Cincinnati, which featured a character with this name. Though it remained more common as a feminine name, it got a boost for boys in 1994 from another television character on the drama Party of Five. In the United Kingdom and Australia it has always been more popular for boys.
As a given name, it was used on the American sitcom Murphy Brown (1988-1998) for both the mother and son of the main character. By 1998 it was more popular as a name for girls in the United States, perhaps further inspired by a character from the movie Jerry Maguire (1996).
This name experienced a rise in popularity at the end of the 20th century. It was the most popular name for girls in England and Wales from 2011 to 2015.