In addition , Warburg had been received by Ferdinand I of Austria .
Carl Warburg was also friends with Prince Metternich , another Austrian politician and statesman , who was one of the most important diplomats of the era .
In addition , Carl Warburg had been received by Ferdinand I of Austrian .
Carl Warburg was also friends with Prince Metternich , another Austrian politician and statesman , who was one of the most important diplomats of the era .