Johann Joseph von Semlin (born Mostafa Ali Mirza Khan; 1736–1824) was the reputed son of Nader Shah. After his father's murder, a loyalist brought Ali Mirza Khan to Maria Theresa in Vienna, Austria, who named him "Johann Joseph Freiherr von Semlin". In 1746, when Von Semlin was 10 years old, he was sent to Graz to learn the German language and European culture. In 1756, he converted to Christianity and two years later returned to Vienna.