This name was initially more common among Eastern Christians in the Byzantine Empire, but it flourished in Western Europe after the First Crusade. In England it became extremely popular, typically being the most common male name from the 13th to the 20th century (but sometimes outpaced by William). During the later Middle Ages it was given to approximately a fifth of all English boys. In the United States it was the most common name for boys until 1923.
The name (in various spellings) has been borne by 21 popes and eight Byzantine emperors, as well as rulers of England, France, Sweden, Denmark, Poland, Portugal, Bulgaria, Russia and Hungary. It was also borne by the poet John Milton (1608-1674), philosopher John Locke (1632-1704), American founding father and president John Adams (1735-1826), and poet John Keats (1795-1821). Famous bearers of the 20th century include author John Steinbeck (1902-1968), assassinated American president John F. Kennedy (1917-1963), and musician John Lennon (1940-1980).
The forms Ian (Scottish), Sean (Irish) and Evan (Welsh) have also been frequently used in the English-speaking world, as has the medieval diminutive Jack.
Due to the renown of the apostle, this name became common throughout the Christian world (in various spellings). In England the Normans introduced it in the Old French form Piers, which was gradually replaced by the spelling Peter starting in the 15th century [1].
Besides the apostle, other saints by this name include the 11th-century reformer Saint Peter Damian and the 13th-century preacher Saint Peter Martyr. It was also borne by rulers of Aragon, Portugal, and Russia, including the Russian tsar Peter the Great (1672-1725), who defeated Sweden in the Great Northern War. Famous fictional bearers include Peter Rabbit from Beatrix Potter's children's books, Peter Pan, the boy who refused to grow up in J. M. Barrie's 1904 play, and Peter Parker, the real name of the comic book superhero Spider-Man.
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-).