Other characters combinations are also possible.
Due to the saint's popularity, the name came into general use in medieval Europe, especially in Spain and France. It was also borne by a 16th-century king of Portugal who died in a crusade against Morocco.
In the early Middle Ages the name was adopted by Norse raiders and settlers in Ireland in the form Njáll. The Norse transmitted it to England and Scotland, as well as bringing it back to Scandinavia. It was also in use among the Normans, who were of Scandinavian origin. A famous bearer of this name was American astronaut Neil Armstrong (1930-2012), the first person to walk on the moon.
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.
It has never been very common as a given name in the English-speaking world, though it rose in popularity after the middle of the 20th century. In the United States it is frequently an African-American name. In Lithuania it may be given in honour of the Lithuanian-American aviator Steponas Darius (1896-1933), who died attempting to fly nonstop from New York to Lithuania. His surname was an Americanized form of the original Darašius.
A famous bearer was the 14th-century Jewish philosopher Abner of Burgos, called Alfonso of Valladolid after he converted to Christianity. It has been used as an English Christian given name since the Protestant Reformation. It was popular with the Puritans, who brought it to America in the 17th century.