He claimed to be the son of King Theodore of Corsica, and adopted the title of Prince of Caprera, serving in the army of King Frederick II of Prussia then acting as agent in London for the Duke of Württemberg.
He was probably an impostor, and according to some intelligence reports may have been a Polish Jew called Wigliawiski.
Though penniless, he managed to gain the acquaintance of those in high circles and was for a time accepted into society.
[1] Frederick wrote an account of his purported father's life, Memoires pour servir a l'histoire de la Corse, and also an English translation, both published in London in 1768.
In 1795 he published an enlarged edition, A Description of Corsica, with an account of its union to the crown of Great Britain.