List of Famous people named William

Sir William Hamilton,, was a British diplomat, antiquarian, archaeologist and vulcanologist. After a short period as a Member of Parliament, he served as British Ambassador to the Kingdom of Naples from 1764 to 1800. He studied the volcanoes Vesuvius and Etna, becoming a Fellow of the Royal Society and recipient of the Copley Medal. His second wife was Emma Hamilton, famed as Horatio Nelson's mistress.

Wilhelm was joint sovereign Duke of Nassau, along with his father's cousin Frederick Augustus, reigning from 1816 until 1839. He was also sovereign Prince of Nassau-Weilburg from 1816 until its incorporation into the duchy of Nassau.

William 'Strata' Smith was an English geologist, credited with creating the first detailed, nationwide geological map of any country. At the time his map was first published he was overlooked by the scientific community; his relatively humble education and family connections prevented him from mixing easily in learned society. Financially ruined, Smith spent time in debtors' prison. It was only late in his life that Smith received recognition for his accomplishments, and became known as the "Father of English Geology".

Count William I of Nassau-Siegen, German: Wilhelm I. Graf von Nassau-Siegen, official titles: Graf zu Nassau, Katzenelnbogen, Vianden und Diez, nicknamed ‘the Elder’ or ‘the Rich’, was since 1516 Count of Nassau-Siegen and of half Diez. He descended from the Ottonian Line of the House of Nassau.

William Joseph Simmons was an American preacher and fraternal organizer who founded and led the second Ku Klux Klan from Thanksgiving evening 1915 until being replaced in 1922 by Hiram Wesley Evans.

William I, Count of Eu, illegitimate son of Richard I, Duke of Normandy, was Count of Eu and Count of Hiémois. William succeeded his nephew, Gilbert, as Count of Eu and Hiémois after his murder in 1040.

Wilhelm, Duke of Saxe-Weimar, was a duke of Saxe-Weimar.

William IV of Hesse-Kassel, also called William the Wise, was the first Landgrave of the Landgraviate of Hesse-Kassel. He was the founder of the oldest line, which survives to this day.