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).
This is also the name of an Irish county, which was itself probably derived from Irish clár meaning "plank, level surface".
The Normans introduced this name to England where it became common among the nobility. Famous medieval literary bearers include the 12th-century chronicler Geoffrey of Monmouth and the 14th-century poet Geoffrey Chaucer, writer of The Canterbury Tales. By the end of the Middle Ages it had become uncommon, but it was revived in the 20th century, often in the spelling Jeffrey.
Though it has never been popular in the English-speaking world among Christians, it has historically been a common name for Jews, who have used it as an Americanized form of names such as Isaac, Israel and Isaiah.
An influential bearer of the name was Martin Luther (1483-1546), the theologian who began the Protestant Reformation. The name was also borne by five popes (two of them more commonly known as Marinus). Other more recent bearers include the German philosopher Martin Heidegger (1889-1976), the American civil rights leader Martin Luther King Jr. (1929-1968), and the American filmmaker Martin Scorsese (1942-).