Young van Heiden fought in the
Caucasus and against the
Hungarian Revolutionary Army, which
Nicholas I assisted the Austrian emperor against. He was promoted to colonel in 1849. During the
Crimean War van Heiden was chief of staff in Baltic Corps, but did not participate in any notable battles. After the war, he was promoted to major general in 1855. In 1854, he married Countess Elisabeth Nikolayevna
Zubova (1833–1894), the daughter of Countess Alexandra
Raimond-Modène (1807–1839). Her father Count
Nikolay Dmitrievich Zubov (1801–1871; ) was Steward of the
Russian Imperial Court, himself the son of princess Paraskeva Viazemskaia and Count Dmitri Alexandrovich Zubov, one of the brothers of Prince
Platon Zubov. Countess Elisabeth was a first cousin of countess Olga
van Suchtelen. After the war, van Heiden was chiefly a member of the General Staff. He participated in
Dmitry Milyutin's military reforms and was appointed as head of the General Staff (Glavni Stab) in 1866. He also chaired the conscription committee that enacted the conscription in Russia in 1874, and was in charge of the mobilization during the
Turkish War, acting as Minister of War during Milyutin's absence during the Turkish War. In 1870, van Heiden was promoted to full general. Eleven years later, he was appointed Governor-General of Finland. ==Governor-General of Finland==