This name was borne by the heroine of Lewis Carroll's novels Alice's Adventures in Wonderland (1865) and Through the Looking Glass (1871).
In the United States this form was much less common than Isabel until the early 1990s, when it began rapidly rising in popularity. It reached a peak in 2009 and 2010, when it was the most popular name for girls in America, an astounding rise over only 20 years.
A famous bearer is the Italian actress Isabella Rossellini (1952-).
Famous bearers include Peyton Randolph (1721-1775), the first president of the Continental Congress, and American football quarterback Peyton Manning (1976-).
Before 1980, this was an uncommon masculine name in America. During the 1980s and 90s this name steadily increased in popularity for both boys and girls, and from 2003 onwards it has been more common for girls in the United States. Elsewhere in the English-speaking world, such as the United Kingdom and Australia, it has remained largely masculine.
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.