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-).
This is not the usual spelling in any of the Scandinavian languages (in Sweden and Denmark it is Freja and in Norway it is Frøja) but it is the common spelling of the goddess's name in English. In the 2000s it became popular in Britain.
As an English name it has been in use since the Middle Ages, originally in the form Clare, though the Latinate spelling Clara overtook it in the 19th century and became very popular. It declined through most of the 20th century (being eclipsed by the French form Claire in English-speaking countries), though it has since recovered somewhat.
In England, this Latin form has been used alongside the vernacular forms Ann and Anne since the late Middle Ages. Anna is currently the most common of these spellings in all English-speaking countries (since the 1970s), however the biblical form Hannah is presently more popular than all three.
The name was borne by several Russian royals, including an 18th-century empress of Russia. It is also the name of the main character in Leo Tolstoy's novel Anna Karenina (1877), about a married aristocrat who begins an ultimately tragic relationship with Count Vronsky.