
After the end of the Napoleonic War, Russia's international prestige reached its peak. When Napoleon's army swept across the continent, Tsarist Russia was the only force that could resist France head-on by the continent. After the victory of the anti-French alliance, Tsar Alexander I rode a white horse into Paris. At this moment, Russia has become the lord of the continent.

However, Alexander I did not live too long. Because he had no heir, his younger brother Nikola became the heir, and this was Nikola I.
took over the empire left by the emperor's brother, and Nicholas I also continued the expansion policies of the tsars of all dynasties. In order to enable the Russian fleet to rush out of Black Sea and enter Mediterranean and Atlantic , Russia must control Turkish Strait , but this wish will inevitably damage the interests of many great powers, among which the opposition from Britain, France and Turkey is the most fierce.

If the Black Sea country wants to go to the Mediterranean, it must pass through the Turkish Strait, including: Bosphorus, Marmara Sea , Dardanelles . The Bosphorus Strait is 30.4 kilometers long, the widest is about 3.6 kilometers, the narrowest is about 708 meters, the deepest is about 120 meters, and the shallowest is only 27.5 meters. In such a narrow and narrow area, passing ships do not have Ottoman Türkiye's passers-by, so it is too difficult to get away with it.

Turkish Strait East and West are both Ottoman territory, and even the capital Istanbul (i.e. Constantinople) are bordered by the Turkish Strait. Turkish cannot agree to the request of Tsar Nicholas I in any case. However, with the lessons from the previous eight "Russia-Turkish Wars", the Ottoman people also understood that they were unable to compete with Russia alone, and Britain and France were also involved.

As a maritime country, what Britain is most worried about is that its maritime hegemony is challenged. Once the Russian fleet enters the Mediterranean from the Black Sea, the geopolitical advantage of the British Navy in this water will be reduced. Although Britain had no good feelings for the Ottoman Empire from religious beliefs and cultural traditions, the British quickly reached an agreement with the Turks in order to curb Russia's expansion.

As for France, it has always wanted to be the European overlord. After the failure of the Napoleonic War, Britain, Russia, Austria and Putra formed a "four-country alliance" to deal with France. France's right to speak in European affairs is subject to this alliance. For the French, as long as the war between Britain and Russia is promoted, the "Four-Country Alliance" will inevitably collapse automatically, so France performed particularly positively in the early stages of the Crimean War.

each had its own needs, Britain, France and Turkey quickly formed an alliance. In 1853, the tragic Crimean War began. Tsarist Russian has about 700,000 troops, with the Ottomans in the coalition, 300,000, Britain has 200,000, and France has 300,000. Tsarist Russia is not at a loss in terms of military strength, but Britain and France have all the advantages of technology and equipment. New weapons such as steam battleship , telegraphs, rifled rifles and other new weapons have appeared one after another, and Russia is exhausted to deal with it.

After three years of war, the Russian army lost more than 522,000 people, the Turkish army lost nearly 96,000 people, the French army lost 95,000 people, and the British army lost 102,000 people. In the end, Tsarist Russia was defeated, but Nicholas I did not persist until after the war.
1855, when the defeat was decided, Tsar Nicholas I suddenly died. His son Alexander II signed a peace treaty with the coalition forces. Russia not only lost all its naval power in the Black Sea, but was also forced to ced large tracts of territory in the west. Its international status was apart from that before the war.

Seeing that the direction of Europe could not be moved, Tsarist Russia accelerated its expansion and competition for the Pacific region, and the geopolitical pattern of the North Pacific changed rapidly.
1855, Japan and Russia divided the Kuril Islands , Japan occupied the south and Tsarist Russia occupied the north.

1860, Qing dynasty and Russian Empire signed the " Sino-Russia Beijing Treaty ", ceding about 400,000 square kilometers of territory east of Ussuri River , including Sakhalin Island to Russia, of which Vladivostok was renamed Vladivostok , meaning "conquer the East".

1867, Russia sold Alaska to the United States for a price of US$7.2 million. There is a very interesting topic now: There is a voice in Russia that we want to buy Alaska back. Of course, unless the United States declines to Ukrainian levels, it is almost impossible for Russia to take back Alaska.