[3] Prince Frederick resigned in December 1781, sent Augusta and their baby son William back to Brunswick and joined his sister Maria Feodorovna and her husband on the Italian leg of their extended tour through Europe.[4] While in Naples, in February 1782, Frederick received an invitation from the Russian Empress to move to St Petersburg as Lieutenant-general in her army and Governor-General of Eastern Finland, with his seat at Viipuri.[4] After spending the summer with Augusta in Montbéliard, his parents' home, they finally arrived in St Petersburg in October 1782, where the Empress had renovated and lavishly furnished a mansion for them.[9] The relationship between Augusta and her abusive husband deteriorated to the point where Catherine wrote an urgent letter to the Duke of Brunswick that his daughter's life was in danger.[21] The sixty-year-old Pohlmann, who had retired to his estate near Lohde six years before, had enjoyed an illustrious career at the Russian Court; he was a close and trusted friend of the Empress, who had appointed him to the board of the prestigious Free Economic Society of Russia.[23] The Empress sold Augusta's house in St Petersburg on her behalf, advised her to invest the money wisely and allowed her to live off the income from the Lohde estate.[27] On the morning of 27 September 1788 (new style), at the age of 23, Augusta suddenly experienced violent vaginal bleeding, which continued for six-and-a-half hours, by which time she died.