Who is Tsar Nicholas I Romanov from Russian Thinkers and what is their importance?

Tsar Nicholas I Romanov ruled Russia from 1825 to 1855. He was also the constitutional King of Poland until 1831, and Grand Duke of Finland. Having two older brothers, he was not raised to rule, but when his oldest brother died, and the second eldest twice refused to rule, Nicholas claimed the throne.

In the confusion, army officers hatched a plan to take power that is now known as the Decembrist rebellion. Nicholas suppressed the rebellion, but it left him opposed to anything that challenged his autocratic power. He sent troops into Poland when its leadership deposed him as constitutional King, reducing it from a semi-autonomous federation to a dependent province of the Russian Empire. After the failed European revolutions of 1848-9, when Russian troops helped suppress a revolt in Hapsburg Austria, Russia under Nicholas was called the "gendarme [policeman] of Europe." The years 1848 to 1855, were among the most repressive of the century in Russia. Nicholas' wars against the Ottoman Empire provoked Western fears of Russian expansion in Europe.