William

William is a popular given name of an old Germanic origin. It became very popular in the English language after the Norman conquest of England in 1066, and remained so throughout the Middle Ages and into the modern era. It is sometimes abbreviated "Wm."Shortened familiar versions in English include Will, Willy, Willie, Bill, and Billy. A common Irish form is Liam. Scottish diminutives include Wull, Willie or Wullie (see Oor Wullie or Douglas for example). Female forms are Willa, Willemina, Willamette, Wilma and Wilhelmina.

William is related to the given name Wilhelm (cf. Proto-Germanic *Wiljahelmaz > German Wilhelm and Old Norse Vilhjálmr). By regular sound changes, the native, inherited English form of the name should be *Wilhelm as well (although the name is not actually attested in the history of English, and the Anglo-Saxon Chronicle refers to William the Conqueror as Willelm). That is a compound of two distinct elements : wil = "will or desire"; helm; Old English helm "helmet, protection"; English helm "knight's large helmet".

In fact, the form William is clearly identified as typical of the Old Norman form Williame, Willame, because first, the English language should have retained (h)elm (see common words helm, helmet), second, -iaume [iaʷm] (typical of Popular French, see Guillaume) turned to -iame [iam] (typical of some Norman and Picard dialects) > English -iam. Historically, there was first a triphthongation of -elm (early Gallo-Romance form ) into [iaʷ] + [m] in Old Norman-French, quite similar in Old Central French [eaʷ] + [m]. Then, the triphthong -iau was submitted to a monophthongation localized on the second part of the triphthong áu > āò > ā. For instance, this development can be followed in the different versions of the name in the Wace's Roman de Rou. or in the Cauchois variant forms of common words such as osias (plural of osè "bird", older oisel) / Regular Norman oisiaus "birds" (French sing. oiseau, pl. oiseaux).

The spelling and phonetics Wi- [wi] is a characteristic trait of the Northern French dialects, but the pronunciation changed in Norman from [wi] to [vi] in the 12th century (cf. the Norman surnames Villon and Villamaux "little William"), unlike the Central French and Southern Norman that turned the Germanic Wi- into Gui- [gwi] > [gi]. The Modern French spelling is Guillaume.

The first well-known carrier of the name was Charlemagne's cousin William of Gellone, a.k.a. Guilhem, William of Orange, Guillaume Fierabrace, or William Short-Nose (755–812). This William is immortalized in the Chanson de Guillaume and his esteem may account for the name's subsequent popularity among European nobility.

The English "William" is taken from the Anglo-Norman language and was transmitted to England after the Norman Conquest in the 11th century, and soon became the most popular name in England, along with other Norman names such as Robert (the English cognate was Hrēodbeorht), Richard, Roger (the English cognate was Hroðgar), Henry and Hugh (all of Germanic origin, transmitted through the Normans' use of Old French).

The name 'Wilkin' is also of medieval origin taken from the shortened version of William (Will) with the suffix "kin" added.

Shortened names

• Bill
• Billy
• Gil
• Will
• Willy, Willie
• Gui
• Wim
• Pim
• Guiguille, Guigui (French language)
• Guille (Spanish)
• Liam
• Memo (Mexico, El Salvador, Costa Rica)
• Yam

Royalty

British

• William I of England (1027–1087), a.k.a. William the Conqueror, or William the Bastard
• William II of England (1056–1100), a.k.a. William Rufus
• William I of Scotland (c. 1142–1214), a.k.a. William the Lion
• William IX, Count of Poitiers (1153–1156), first son of Henry II of England
• William III of England (1650–1702), also William II of Scotland, a.k.a. William of Orange
• William IV of the United Kingdom (1765–1837), King of the United Kingdom of Great Britain and Ireland and King of Hanover from 26 June 1830 until his death
• Prince William, Duke of Cambridge (born 1982), formerly Prince William of Wales, son of Charles, Prince of Wales

Dutch

• William I, Count of Holland (1167–1222), Count of Holland
• William II of Holland (1228–1256), also King of Germany
• William I, Prince of Orange (1533–1584), a.k.a. William the Silent
• William II, Prince of Orange (1626–1650), stadtholder of the United Provinces of the Netherlands
• William III of Orange (1650–1702), also William III of England and William II of Scotland
• William I of the Netherlands (1772–1843), Prince of Orange and the first King of the Netherlands and Grand Duke of Luxembourg
• William II of the Netherlands (1792–1849), King of the Netherlands, Grand Duke of Luxembourg, and Duke of Limburg
• William III of the Netherlands (1817–1890), King of the Netherlands, Grand Duke of Luxembourg, and Duke of Limburg
• William IV, Prince of Orange (1711–1751), first hereditary Stadtholder of all the United Provinces
• William V, Prince of Orange (1748–1806), last Stadtholder of the Dutch Republic

French

• William of Gellone (c.755–814), Count of Toulouse, canonized a saint

German

• William I, (1797–1888), Emperor of Germany and King of Prussia
• William II (1859–1941), Emperor of Germany and King of Prussia

Sicilian

• William I of Sicily (1131–1166), a.k.a. William the Bad or William the Wicked
• William II of Sicily (1155–1189), a.k.a. William the Good
• William III of Sicily (1190–1198), last Norman King of Sicily, reigning briefly for ten months in 1194

Cameroon

• William I of Bimbia, 19th-century king of the Isubu people
• William II of Bimbia (died 1882), king of the Isubu people

Other

• William II of Villehardouin (died 1278), Prince of Achaea
• William of Werle (died 1436/94-1436), Lord of Werle-Güstrow
• William IV, Grand Duke of Luxembourg (1852–1912)
• William, Prince of Albania (1876–1945), from March to September 1914

Pre-modern era

British

• William (bishop of the Isles) (died 1095), bishop of what later became the Diocese of the Isles
• William de Corbeil (c. 1070–1136), Archbishop of Canterbury
• William of Malmesbury (died 1143), English historian and monk
• William of Tyre (c. 1130–1185), Archbishop of Tyre, chronicler of the Crusades
• William of Norwich (c. 1132–1144), saint and martyr
• William of York (died 1154), Archbishop of York and saint
• William (bishop of Moray) (died 1162), Roman Catholic bishop in Scotland
• William Marshal, 1st Earl of Pembroke (1146/7-1219), Anglo-Norman soldier and statesman
• William of Ramsey (fl. 1219), English monk and hagiographer
• William (bishop of Dunblane) (died early 1290s), Tironensian abbot and bishop in the Kingdom of Scotland
• William Wallace (c.  1270–1305), Scottish general and one of the main leaders during the Wars of Scottish Independence
• William of Ockham (1287–1347), English friar and philosopher, originator of Occam's Razor
• William of Wykeham (1320–1404), Bishop of Winchester, founder of Winchester College and New College, Oxford
• William Caxton (c. 1422–c. 1491), English merchant, diplomat and writer, thought to be the first person to introduce a printing press into England

French

• William Longsword (r. 927–942), second duke of Normandy
• William the Conqueror (c. 1028–1087), Duke of Normandy and first Norman king of England
• William of Poitiers (c. 1020–1090), Norman chronicler, chaplain to William the Conqueror
• William de St-Calais (died 1096), Norman abbot, Bishop of Durham
• William (bishop of Orange) (died 1098), took part in the First Crusade
• William of Champeaux (1070–1121), French philosopher and theologian
• William of Conches (c. 1090–c. 1154), French scholastic philosopher, tutor of Henry II of England
• William of Donjeon (c. 1155–1209), a.k.a. St. William of Bourges and St. William the Confessor, French archbishop
• William the Clerk (fl. c. 1200–c. 1240), Old French poet, writer of the Roman de Fergus
• William the Clerk of Normandy (fl. 1210/1211–1227/1238), Norman cleric and Old French poet
• William of Auxerre (died 1231), French theologian

Other

• William (marcha orientalis) (died 871), Margrave of the March of Pannonia, part of the Carolingian Empire
• William (archbishop of Mainz) (929–968), German bishop, son of Emperor Otto the Great
• William of St-Thierry (died 1148), theologian and mystic, abbot of St. Thierry
• William of Moerbeke (1215–1286), Flemish bishop, translator of philosophical, medical, and scientific texts

Modern era

• William Jennings Bryan (1860–1925), American orator and politician
• Bill Clinton (born 1946), 42nd president of the United States
• William J. Donovan (1883–1959), American soldier, lawyer, intelligence officer and diplomat
• William Douglas (disambiguation)
• William Faulkner (1897–1962), American writer
• Bill Gates (born 1955), American business magnate, investor, author, philanthropist, humanitarian and programmer
• William Harrison (disambiguation)
• William Randolph Hearst Sr. (1863–1951), American businessman, newspaper publisher and politician
• William Holden (1918–1981), American actor
• William McKinley (1843–1901), 25th president of the United States
• William Shakespeare (1564–1616), English poet, playwright and actor
• William Howard Taft (1857–1930), 27th president of the United States (1909–1913) and the tenth chief justice of the United States
• William Pitt, 1st Earl of Chatham or William Pitt the Elder (1708–1778), British statesman and prime minister
• William Pitt the Younger (1759–1806), British statesman and prime minister
• William Wilberforce (1759–1833), British politician, philanthropist and abolitionist
• William Witherle Lawrence (1876-1936), American philologist
• William Wordsworth (1770–1850), English poet

• William Brown, main character of the Just William novel series
• Baby William, son of Dana Scully and Fox Mulder in the American television series, The X-Files
• Father William, comical character in Lewis Carroll's Alice's Adventures in Wonderland
• William Dunbar, character from the French animated television series Code Lyoko
• William the Bloody, vampire from Buffy the Vampire Slayer television series.
• William Turner, character of the Pirates of the Caribbean franchise.