Nicholas I reigned as Emperor of Russia, King of Congress Poland and Grand Duke of Finland from 1825 until 1855. He was the third son of Paul I and younger brother of his predecessor, Alexander I. Nicholas inherited his brother's throne despite the failed Decembrist revolt against him. He is mainly remembered in history as a reactionary whose controversial reign was marked by geographical expansion, economic growth and massive industrialisation on the one hand, and centralisation of administrative policies and repression of dissent on the other. Nicholas had a happy marriage that produced a large family; all of their seven children survived childhood.
Nicholas' biographer Nicholas V. Riasanovsky said that he displayed determination, singleness of purpose, and an iron will, along with a powerful sense of duty and a dedication to very hard work. He saw himself as a soldier—a junior officer totally consumed by spit and polish. A handsome man, he was highly nervous and aggressive. Trained as an engineer, he was a stickler for minute detail.