List of Famous people named William

William de Burgh, 3rd Earl of Ulster and 4th Baron of Connaught was an aristocrat in the Peerage of Ireland. His murder at age 20 led to the Burke Civil War.

William I, called the Pious, was the Count of Auvergne from 886 and Duke of Aquitaine from 893, succeeding the Poitevin ruler Ebalus Manser. He made numerous monastic foundations, most important among them the foundation of Cluny Abbey on 11 September 910.

William II was the penultimate Elector of Hesse.

William Hardy McNeill was a historian and author, noted for his argument that contact and exchange among civilizations is what drives human history forward, first postulated in The Rise of the West (1963). He was the Robert A. Millikan Distinguished Service Professor Emeritus of History at the University of Chicago, where he taught from 1947 until his retirement in 1987.

William Parsons, 3rd Earl of Rosse HFRSE, was an Anglo-Irish astronomer who had several telescopes built. His 72-inch telescope, built in 1845 and colloquially known as the "Leviathan of Parsonstown", was the world's largest telescope, in terms of aperture size, until the early 20th century. From April 1807 until February 1841, he was styled as Baron Oxmantown.

William Farel, Guilhem Farel or Guillaume Farel, was a French evangelist, Protestant reformer and a founder of the Reformed Church in the Principality of Neuchâtel, in the Republic of Geneva, and in Switzerland in the Canton of Bern and the Canton of Vaud. He is most often remembered for having persuaded John Calvin to remain in Geneva in 1536, and for persuading him to return there in 1541, after their expulsion in 1538. They influenced the government of Geneva to the point that it became the "Protestant Rome", where Protestants took refuge and non-Protestants were driven out. Together with Calvin, Farel worked to train missionary preachers who spread the Protestant cause to other countries, and especially to France.

William of Ockham was an English Franciscan friar, scholastic philosopher, and theologian, who is believed to have been born in Ockham, a small village in Surrey. He is considered to be one of the major figures of medieval thought and was at the centre of the major intellectual and political controversies of the 14th century. He is commonly known for Occam's razor, the methodological principle that bears his name, and also produced significant works on logic, physics, and theology. In the Church of England, his day of commemoration is 10 April.

William de Valence, born Guillaume de Lusignan, was a French nobleman and knight who became important in English politics due to his relationship to King Henry III of England. He was heavily involved in the Second Barons' War, supporting the King and Prince Edward against the rebels led by Simon de Montfort. He took the name de Valence after his birthplace, Valence, near Lusignan.

William John Macquorn Rankine was a Scottish mechanical engineer who also contributed to civil engineering, physics and mathematics. He was a founding contributor, with Rudolf Clausius and William Thomson, to the science of thermodynamics, particularly focusing on the first of the three thermodynamic laws. He developed the Rankine scale, an equivalent to the Kelvin scale of temperature, but in degrees Fahrenheit rather than Celsius.