This later drew Frederick and his family into the Prussian king's network of marriage alliances—in 1776 his sister Sophie would marry to Tsesarevich Paul, future Emperor of Russia and son of Empress Catherine II.

In 1781 Frederick resigned from the Prussian Army as a major general and the following year he accompanied his sister Sophie and her husband Paul to Russia, after a Grand Tour of Europe that the imperial couple had undertaken in France and Italy.

Pleased with the well-spoken and confident young man, Catherine II appointed Frederick Governor of Eastern Finland, with his seat at Viipuri.

When Sophie protested at the treatment of her brother, Catherine replied, "It is not I who cover the Prince of Württemberg with opprobrium: on the contrary, it is I who try to bury abominations and it is my duty to suppress any further ones."

Augusta was sent to live at Lohde Castle in Western Estonia but died on 27 September 1788 from complications of amenorrhea, which she had been suffering from for several years,[1] and although rumours were spread about a death from miscarriage they were disproven through an exhumation later.

In June 1789 he traveled to Paris to see the first stages of the French Revolution at first hand, before moving to Ludwigsburg the following year, much to the displeasure of his uncle Carl Eugen, who was still on the throne.

In the Reichsdeputationshauptschluss, which reorganized the Empire as a result of the French annexation of the west bank of the Rhine, the Duke of Württemberg was raised to the dignity of Prince-elector.

The reorganization of the Empire also secured the new Elector control of various ecclesiastical territories and former free cities, thus greatly increasing the size of his domains.

In exchange for providing France with a large auxiliary force, Napoleon allowed Frederick to raise Württemberg to a kingdom on 26 December 1805.

During the German campaign of 1813, Frederick changed sides and went over to the Allies, where his status as the brother-in-law of the British Prince Regent (later George IV) and uncle to the Russian emperor Alexander I helped his standing.

In the end, however, Austria, which was seen as the natural ally of the princes, was more interested in alliance with the medium-sized German states like Württemberg than in asserting its traditional role as protector of the smaller sovereigns of the old Empire; and Frederick was allowed to retain his dubiously acquired lands.

[citation needed] He married twice: The then Erbprinz of Württemberg was awarded most of his honorary titles on his trip to England in 1797[4]: Miliary ranks Frederick held before rising to the throne: