| 23 May 1815 |
22 August 1815 |
Treaty of Accession of Hess-Darmstadt to the Treaty of Alliance of 25 March 1815 |
| 16 April 1856 |
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Declaration respecting Maritime Law, signed by the Plenipotentiaries of Great Britain, Austria, France, Prussia, Russia, Sardinia, and Turkey, assembled in Congress at Paris - April 16, 1856 |
| 14 August 1861 |
|
Treaty between Great Britain and Hesse, for the Marriage of Her Royal Highness the Princess Alice Maud Mary with His Grand Ducal Highness the Prince Frederick William Lewis Charles of Hesse |
| 22 August 1864 |
22 June 1865 |
Convention for the Amelioration of the Condition of the Wounded in Armies in the Field |
| 10 July 1885 |
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Articles for the Marriage of Her Royal Highness the Princess Beatrice Mary Victoria Feodore and His Serene Highness the Prince Henry Maurice of Batternberg, Son of His Grand Ducal Highness Prince Alexander of Hesse |