Rantzau had led an adventurous and dishonourable career. In his youth he had been a chamberlain at the Danish court, and had served in the army, eventually rising to the rank of major-general. In consequence of a court plot, he was banished from Copenhagen in 1752. He then entered the French army, but in Paris he became enamoured of an opera singer and resigned his commission to follow her about Europe. This part of his career, which occupied nearly ten years, was shrouded in mystery, but it was known that during it Rantzau had many scandalous adventures. Sometimes he travelled with all the luxury befitting his rank and station, at others he was at his wits' end for money. At one time he lived at Rome, habited as a monk, and at another he travelled _incognito_ with a troupe of actors. He had absolutely no scruples, and seemed to be a criminal by nature. He was tried in Sicily for swindling, and only escaped imprisonment through the influence brought to bear on his judges. At Naples there was an ugly scandal of another nature, but the French envoy intervened, and saved him from punishment, in consideration of his birth and rank. In Genoa he got into trouble through drawing a bill on his father, whom he falsely described as the "Viceroy of Norway," but his father repudiated the bill, as he had already repudiated his son, and again Rantzau narrowly escaped gaol. With such a record Keith was certainly justified in saying of him: "Count Rantzau would, ... if he had lived within reach of Justice Fielding, have furnished matter for an Old Bailey trial any one year of the last twenty of his life".[130] [130] _Memoirs and Correspondence of Sir R. Murray Keith._