The epitome of his career was the Russo-Turkish War, 1877–1878, when Nicholas Nicolaievich was appointed Commander-in-Chief of the Russian armies of the Danube, although his reputation as a strategist was very low.

After the expulsion of the Russian troops from Rumelia and unsuccessful attacks at Plevna, Nicholas Nicolaievich was removed from actual command [citation needed], although in theory he remained in his post.

The Grand Duke also suffered the acute embarrassment of being charged with financial irregularities, of receiving bribes and embezzling money from the government.

His brother, Alexander II, promoted Nicholas Nicolaievich's career and named him Commander of the St Petersburg military region.

The Grand Duke Nicholas Nicolaievich took great interest in managing his estates, but he failed to inspire affection, even in those closest to him.

They had two children: The marriage was in trouble from the start and four years later, Nicholas developed a permanent relationship with Catherine Chislova, a dancer from the Krasnoye Selo Theater.

Nicholas Nicolaievich was in Cannes with his two sons when his brother Alexander II was assassinated, returning immediately to Russia in March 1881.

The ascension to the Russian throne of his nephew, Alexander III, marked the beginning of the Grand Duke's steady decline.

When the Grand Duke tried to explain his actions to the Nouvelle Revue of Paris 1880, he indiscreetly attacked government officials and military commanders and eventually was removed from his post.

[4] In 1882, Nicholas Nicolaievich was put under supervision due to the squandering of his fortune; he lived as a private gentleman in a modest house.