Born in
Schwerin, Clewing originates from an old Westphalian
Schulzengeschlecht, which is first mentioned in documents in 1486 on the Schulte-Klevinghof in the parish
Pelkum. In his birthplace Schwerin, his father was the owner of the Löwenapotheke (Lion Pharmacy) there. Clewing studied in Prague and joined the
Burschenschaft there, Constantia, which was absorbed into the Munich fraternity Sudetia in 1952. From 1909 he was an actor in Berlin and in 1911 he was appointed as a royal court actor, in the same year he made his film debut as a film actor in ''
. At the outbreak of World War I he volunteered, was first runner and at the end of 1914 he belonged to the parliamentary group under the leadership of Achim von Arnim which called on Reims to hand over the theatre. Rudolf Binding has literally processed this episode in the story Wir fordern Reims zur Ubergabe auf''. Later Clewing was also a fighter pilot and got to know
Hermann Göring. During the war he was awarded several times and promoted to lieutenant. Because of his artistic activity in front of front- and invalids troops of the Central Powers (see below
Awards) he was active after the war again in Berlin as an opera singer but also as a film actor. In 1922 he became a guest lecturer and professor at the state conservatory of the Hochschule für Staats- & Wirtschaftswissenschaften in
Detmold. In autumn 1922 he had an engagement as a heldentenor at the
Staatsoper Unter den Linden. In 1924/25 he took part in the
Bayreuth Festival and sang
Walter von Stolzing and
Parsifal. During this time he also developed a small form of the , which is also called ''Clewing's Pocket Hunting Horn'' in his memory. On 27 May 1938, Clewing gave a lecture on the subject of
Singing and Speaking at the
Reichsmusiktage. (published in association with
Hans Felix Husadel, 1939) and
Adlerliederheft. Feldausgabe des Liederbuches der Luftwaffe (1941) were placed on the
list of literature to be excluded. == Family ==