Tolkien's immediate paternal ancestors were middle-class craftsmen who made and sold clocks, watches and pianos in London and Birmingham. The Tolkien family originated in the East Prussian town Kreuzburg near Königsberg, which was founded during medieval German eastward expansion, where his earliest-known paternal ancestor Michel Tolkien was born around 1620. Michel's son Christianus Tolkien (1663–1746) was a wealthy miller in Kreuzburg. His son Christian Tolkien (1706–1791) moved from Kreuzburg to nearby Danzig, and his two sons Daniel Gottlieb Tolkien (1747–1813) and Johann (later known as John) Benjamin Tolkien (1752–1819) emigrated to London in the 1770s and became the ancestors of the English family; the younger brother was J. R. R. Tolkien's second great-grandfather. In 1792 John Benjamin Tolkien and William Gravell took over the Erdley Norton manufacture in London, which from then on sold clocks and watches under the name Gravell &amp; Tolkien. Daniel Gottlieb obtained British citizenship in 1794, but John Benjamin apparently never became a British citizen. Other German relatives also joined the two brothers in London. Several people with the surname Tolkien or similar spelling, some of them members of the same family as J. R. R. Tolkien, live in northern Germany, but most of them are descendants of people who evacuated East Prussia in 1945, at the end of World War II.