As an English name it can also derive from the month of August, which was named for the Roman emperor Augustus.
Because Elijah was a popular figure in medieval tales, and because his name was borne by a few early saints (who are usually known by the Latin form Elias), the name came into general use during the Middle Ages. In medieval England it was usually spelled Elis. It died out there by the 16th century, but it was revived by the Puritans in the form Elijah after the Protestant Reformation. The name became popular during the 1990s and 2000s, especially in America where it broke into the top ten in 2016.
This name has been used occasionally in England since the 12th century. It was not common in the English-speaking world until the end of the 20th century.
This name was later borne by three other English kings, as well as rulers of Scotland, Sicily (of Norman origin), the Netherlands and Prussia. Other famous bearers include William Wallace, a 13th-century Scottish hero, and William Tell, a legendary 14th-century Swiss hero (called Wilhelm in German, Guillaume in French and Guglielmo in Italian). In the literary world it was borne by dramatist William Shakespeare (1564-1616), poet William Blake (1757-1827), poet William Wordsworth (1770-1850), dramatist William Butler Yeats (1865-1939), author William Faulkner (1897-1962), and author William S. Burroughs (1914-1997).
In the American rankings (since 1880) this name has never been out of the top 20, making it one of the most consistently popular names (although it has never reached the top rank). In modern times its short form, Liam, has periodically been more popular than William itself, in the United Kingdom in the 1990s and the United States in the 2010s.