Theodore Roosevelt | Theodore Dreiser | Theodore Sturgeon | Theodore von Kármán | Theodore Roosevelt, Jr. | Adolphe Thiers | Theodore Parker | Theodore Bikel | Theodore | Theodore Roosevelt National Wildlife Refuge Complex | Théodore Botrel | Edmond Adolphe de Rothschild | Charles Theodore, Elector of Bavaria | Adolphe Menjou | Adolphe, Grand Duke of Luxembourg | Theodore Wirth | Theodore Ushev | Theodore Robinson | Theodore of Tarsus | Theodore Edgar McCarrick | Théodore Dubois | Theodore Roethke | Theodore of Mopsuestia | Théodore Géricault | Theodore Dru Alison Cockerell | Théodore Dézamy | Theodore C. Blegen | John Theodore of Bavaria | Charles Theodore | Adolphe Quetelet |
In botany, in addition to a memoir on the minute structure of Volvox (1852), his work on the structure of fossil plants established British palaeobotany on a scientific basis; Williamson ranks with Adolphe Theodore Brongniart as one of its founders.