Prince Heinrich of Hesse and by Rhine (Heinrich Ludwig Wilhelm Adalbert Waldemar Alexander; 28 November 1838 — 16 September 1900) was a member of the House of Hesse-Darmstadt and a General of the Cavalry.
He was the second son of Prince Charles of Hesse and by Rhine and Princess Elisabeth of Prussia and a younger brother of the later Louis IV, Grand Duke of Hesse.
Heinrich studied in Göttingen and Giessen and joined the Hessian army as a lieutenant in 1854. In 1859 he joined the Prussian Army as a captain and fought in the First Schleswig War and the Austro-Prussian War.
On 17 September 1866 Heinrich became commander of the 2nd Guards Uhlan Regiment. He led the regiment during the Franco-Prussian War and received the Iron Cross (2nd class). In 1873, Heinrich was promoted to Generalmajor. In 1879 he became commander of the 25th (Grand Ducal Hessian) Division and shortly afterwards was promoted to Lieutenant General. On 21 August 1884 Heinrich was given the distinction of a Commanding General and two years later, on 18 September 1886, was promoted to General of the Cavalry. On 7 July 1887, Heinrich retired and received the Pour le Mérite; being the final recipient by order of William I as the latter died in the next year.
In retirement he eventually settled in Munich. From 1881 until his death he also was a member of the Hessian Landstände.
Heinrich married morganatically on 25 February 1878, Caroline Willich von Pöllnitz (1848-1879), member of petite nobility of Hesse. Caroline was created Freifrau von Nidda for the occasion. She died after the birth of their only child Karl, Count of Nidda (1879-1920).
He married again in 1892 - also morganatically, to Emilie Hrzic de Topuska (1868-1961), member of the minor Croatian nobility. She was elevated to Freifrau von Dornberg. They had also one son: Elimar, Freiherr von Dornberg (1893-1917), who died in an accident.
He received the following orders and decorations:[1]