Wilhelm (William) von Rosenberg, surveyor, topographer, and chronicler of German immigration to Texas, son of Johanna Dorothea (Frölich) and Peter Carl Johann von Rosenberg, was born on his father's estate, Eckitten, near Memel, East Prussia, on October 14, 1821. He was descended from an ancient line of German nobles dating back to the twelfth century. Like others of his class, he spent his youth in formal schooling. He completed high school and an apprenticeship to a surveyor, and in 1841 he entered military service. After serving three years in the Prussian Army, he was commissioned a lieutenant in the reserves. In 1845 he passed the government examination for surveyor at the Royal Academy in Berlin, and from 1846 to 1848 he studied architecture in Berlin and received credentials as a government (royal) architect. His outspoken democratic views in an aristocratic political climate, however, prompted the resignation of his military commission in 1849 and the decision to emigrate to America.
Accompanied by his family, including his parents, six brothers and sisters, and a new wife, Auguste Franziska (Anders), Rosenberg landed in Galveston in December 1849. The Rosenbergs settled on Nassau Farm near Round Top, Fayette County, and during the next six years Wilhelm farmed, learned English, adopted the Anglicized name William, and became a United States citizen. His skillful execution of a design for the Fayette County courthouse in La Grange led to an appointment in 1856 as draftsman in the General Land Office in Austin. In 1861 he became chief draftsman, a position he held until 1863, when he became a topographical engineer with the rank of captain in the Confederate Army. At the close of the Civil War Democrat William von Rosenberg returned to the General Land Office as chief draftsman. He resigned from that post in 1867, when the land office was filled with anti-Confederate, Republican, Reconstruction appointees, many of whom were also German. He then entered into partnership with former state comptroller Clement R. Johns, who operated a land agency in Austin. In 1876 the firm collapsed, and in 1877 Rosenberg opened his own land agency, which he operated until his death on December 4, 1901, in Austin. Rosenberg was the author of Kritik (1894), the first critical account of German immigration to Texas (see ADELSVEREIN), documented by original research in the State Archives and the General Land Office. He was a founding member of St. Martin's Evangelical Lutheran Church in Austin. He had twelve children, including Ernst (1852–1915), who also became chief draftsman in the General Land Office, and William, Jr. (1859–1919), who served three terms as Travis county judge.