Thomas Martin Einstein
Albert Einstein had three children, Lieserl Maric (1902–1903?), Hans Albert Einstein (1904–1973), and Eduard "Tete" Einstein (1910–1965), but only Hans Albert is known to have married and had children. Hans Albert's only biological child to survive to adulthood was Bernard Caesar Einstein (1930–2008), who was a physicist and the father of Thomas Martin Einstein.
Zoellner Quartet
More than a dozen years later, in January 1931, Albert Einstein, who was then engaged in research at the California Institute of Technology, visited the Zoellner family's conservatory and played violin with members of the quartet in music of Beethoven and Mozart. The following year, a few days before Einstein sailed for what would be his last visit to Germany, he presented Joseph Zoellner with an autographed photograph as a memento of the occasion.