Arthur is the name of the central character in Arthurian legend, a 6th-century king of the Britons who resisted Saxon invaders. He may or may not have been based on a real person. He first appears in Welsh poems and chronicles (perhaps briefly in the 7th-century poem Y Gododdin and more definitively and extensively in the 9th-century History of the Britons [1]). However, his character was not developed until the chronicles of the 12th-century Geoffrey of Monmouth [2]. His tales were later taken up and expanded by French and English writers.
The name came into general use in England in the Middle Ages due to the prevalence of Arthurian romances, and it enjoyed a surge of popularity in the 19th century. Famous bearers include German philosopher Arthur Schopenhauer (1788-1860), mystery author and Sherlock Holmes creator Arthur Conan Doyle (1859-1930), and science-fiction author Arthur C. Clarke (1917-2008).
Heinrich was popular among continental royalty, being the name of seven German kings, starting with the 10th-century Henry I the Fowler (the first of the Saxon kings), and four French kings. In France it was usually rendered Henri from the Latin form Henricus.
The Normans introduced the French form to England, and it was subsequently used by eight kings, ending with the infamous Henry VIII in the 16th century. During the later Middle Ages it was fairly popular, and was generally rendered as Harry or Herry in English pronunciation. Notable bearers include arctic naval explorer Henry Hudson (1570-1611), American-British novelist Henry James (1843-1916), American automobile manufacturer Henry Ford (1863-1947), and American actor Henry Fonda (1905-1982).
The English names Jacob and James derive from the same source, with James coming from Latin Iacomus, a later variant of the Latin New Testament form Iacobus. Unlike English, many languages do not have separate spellings for the two names.
In England, Jacob was mainly regarded as a Jewish name during the Middle Ages [1], though the variant James was used among Christians. Jacob came into general use as a Christian name after the Protestant Reformation. In America, although already moderately common, it steadily grew in popularity from the early 1970s to the end of the 1990s, becoming the top ranked name from 1999 to 2012.
A famous bearer was Jacob Grimm (1785-1863), the German linguist and writer who was, with his brother Wilhelm, the author of Grimm's Fairy Tales.
As an English name, Jonathan did not become common until after the Protestant Reformation. A famous bearer was the Anglo-Irish satirist Jonathan Swift (1667-1745), who wrote Gulliver's Travels and other works.