in St Petersburg, by
Boris Orlovsky Barclay was enlisted in the
Pskov Carabineer Regiment on 13 May 1776, and he achieved the rank of a
cornet by May 1778. In the same year, he joined the Imperial
jaeger regiments, and with his unit was assigned to the army of
Prince Potemkin. In 1788–1789, during the
Russo-Turkish War (1787–92), Barclay served under the command of
Victor Amadeus of Anhalt-Bernburg-Schaumburg-Hoym. During this campaign, he distinguished himself in the taking of
Ochakov and
Akkerman. For his role in the capture of Ochakov, he was personally decorated by Prince Potemkin. In 1789, during the Russo-Swedish War, he was transferred to the Finnish front. Four years later, he fought in the
Polish Campaign of 1794, and was decorated for his role in the capture of
Vilnius. He was a lieutenant colonel by 1794 after serving as
aide-de-camp to various senior officers in several campaigns. In that year, he was appointed commander of the Estland Jaeger Corps, and three years later commander of the 4th Jaeger Regiment, becoming its chief in 1799, soon after being promoted to general major for his service in
Poland. In the war of 1806 against Napoleon, Barclay took a distinguished part in the
Battle of Pultusk (December 1806) and was wounded at the Battle of Eylau (7 February 1807), where his conduct won him promotion to the rank of
lieutenant general. After a period of convalescence, Barclay returned to the army and in 1808 commanded operations against the Swedes during the
Finnish War. In 1809, he successfully marched over the frozen
Gulf of Bothnia, which allowed him to surprise the enemy and seize
Umeå in Sweden. For this exploit, immortalized by the Russian poet
Baratynsky, he was made
full general, namely a
general of the infantry, and Governor-General of Finland. A year later, he became Minister of War, retaining the post until 1813. == Napoleon's invasion ==