Background
She was the fourth child and second (but eldest and only surviving) daughter of Karl Johann Baptist, 7th Prince of Dietrichstein, and Maria Christina Josepha, a daughter of January Josef František Antonín, Count of Thun-Hohenstein.
She was the fourth child and second (but eldest and only surviving) daughter of Karl Johann Baptist, 7th Prince of Dietrichstein, and Maria Christina Josepha, a daughter of January Josef František Antonín, Count of Thun-Hohenstein.
The wedding took place in the Imperial court at Vienna on 27 August 1787: however, the union was extremely unhappy and the groom abandoned Theresia almost immediately after. The formal separation was pronounced in 1788, but either spouse was freed to remarry because according to the Catholic precepts they still bonded to each other. Since 1798, Theresia became close to Maximilian, Count of Merveldt, General of Cavalry and ambassador in the Russian and English courts.
Theresia and Maximilian of Merveldt married on 16 February 1807 in Saint St. Petersburg, where the groom was the Imperial ambassador at that time.
After only eight years of marriage, Maximilian of Merveldt died in 1815. Theresia never remarried and died eight years later, aged 54.