"Grand Duke Konstantin Nikolaevich of Russia (Russian: Константи́н Никола́евич Рома́нов; 21 September 1827 – 25 January 1892) was the second son of Tsar Nicholas I of Russia and younger brother of Tsar Alexander II.
During the reign of Alexander II, Konstantin was an admiral of the Russian fleet and reformed the Russian Navy. He was also an instrumental figure in the emancipation of the serfs. He was less fortunate as viceroy of Poland (1862–1863) and had to be recalled to Russia where he was attacked for his liberalism.
After the assassination of his brother Alexander II in 1881, Konstantin fell from favour. The new tsar, Alexander III, his nephew, opposed Konstantin´s liberal ideas and gradually stripped him of all his governmental positions. His retirement was marked with personal turmoil and family setbacks. After suffering a stroke, he spent his last years as an invalid." - (en.wikipedia.org 08.11.2019)
