On 15 October 1780, at the age of 15, Augusta was married in Brunswick to Prince Frederick of Württemberg, eldest son of Frederick Eugene, himself the youngest brother of the reigning Charles Eugene, Duke of Württemberg. As neither the reigning Duke nor his other older brother had any sons, Frederick's father was expected to succeed in time as Duke of Württemberg. That eventuality was however many years in the future, and the birth of a legitimate heir would end Frederick's hopes conclusively. Moreover, his uncle the Duke was not disposed to give any member of his family any role in affairs of government. Frederick therefore determined to make a career abroad. His sister Sophie was married to Tsesarevich Paul, future Emperor of Russia. In 1782, Frederick accompanied Sophie and her husband to Russia, following a Grand Tour of Europe that the imperial couple had undertaken. Pleased with the well-spoken and confident young man, the Empress Catherine II appointed Frederick Governor-General of Eastern Finland, with his seat at Viipuri.
Separation
Augusta joined her husband in Viipuri. In the next five years, the couple would become the parents of four children. However, Augusta and Frederick did not have a happy marriage. During a visit to Saint Petersburg in December 1786, Augusta fled to the apartments of Empress Catherine to ask for protection. She alleged that Frederick was bisexual, that he had a coterie of young noblemen, and that he was violent towards her. A horrified Catherine gave Augusta asylum in her palace and sent word to Frederick that it would be best for him to leave Russia, at least for the time being. Sophie protested at this treatment of her brother, and Catherine replied curtly, "It is not I who cover the Prince of Württemberg with : on the contrary, it is I who try to bury abominations, and it is my duty to suppress any further ones." Augusta's father was less sympathetic, and he refused his daughter's plea for a divorce when she sent the request to him from Russia. Before he left, Frederick made it known through Sophie to the Empress that he regarded his wife to be as of "poor character" as she behaved with too much informality with servant-lads, grooms and aides, and that the "violence" she accused him of was only his insistence that she should behave with adequate reserve towards them, in keeping with what was regarded as suitable for a woman of her high rank. The allegation of bisexuality was never made known to him, but it is notable that Frederick later had a happy marriage, with no hint of either bisexuality or violence, with Princess Charlotte of Great Britain.
Affair and death
After Augusta's father had refused to countenance a divorce, and with Augusta showing clear signs of proving her husband right in the matter of behavior with men of lower rank, Catherine found it necessary to make arrangements for her removal from the palace. She gave Augusta the use of one of her Imperial estates, Lohde castle, in Lohde in Kullamaa Parish to the south-west of Tallinn, Estonia. Augusta was put in the custody of Wilhelm von Pohlmann, a former hunt-master. Augusta quickly began a sexual relationship with her custodian, and soon became pregnant by him. On 27 September 1788, aged 23, Augusta went into premature labour with a stillborn child, followed by hemorrhaging. Pohlmann refused to send for a doctor or any other medical help, fearful that his illegitimate relationship to her would be exposed. Augusta died of blood loss. She was hurriedly buried in an unmarked grave in the church at Koluvere. Brief letters were then written to the Empress Catherine and to Augusta's father in Brunswick, blandly announcing her death and giving the cause as the breaking of a blood vessel. Sightings of Augusta were reported for several years in the vicinity of Lohde castle, which suggests some local belief of scandal, tragedy or foul play, but no sighting proved to be true. The facts of her death only came to light many years later, when her eldest son had the matter investigated and her body was exhumed. Augusta's story was fictionalized by Thackeray in The Luck of Barry Lyndon. She is buried in Kullamaa church. On her tombstone is the text: "Hic jacet in pace Augusta Carolina Friderica Luisa Ducis Brunsuicencis-Guelferbytani Filia Friderici Guilielmi Caroli Ducis Vurtembergensis et Supremi Praefecti Viburgiensis Uxor Nat. d. III. Dec. MDCCLXIV Denat. d. XIV. Sept. MDCCLXXXVIII" The castle and lands of Koluvere were afterwards granted to Count Frederik Vilhelm Buxhoevden.
