Louis IV (1837-1892) was the Grand Duke of Hesse and by Rhine from 1877 to 1892.
Hessian Tribute - Alice & Louis IV - 1862-2012 - YouTube (https://www.youtube.com/watch?v=0Xd8BPr9Pkk)
Louis' wife, Princess Alice was very supportive of her husband, particularly when his father Prince Charles died inn 1877, leaving Prince Louis as his uncle's heir.
On the day of his wedding, July 1, 1862, Queen Victoria issued a royal warrant granting Louis the style of Royal Highness in the United Kingdom.
In the Franco-Prussian War in 1870, Prince Louis was credited with courageous military service, especially at the Battle of Gravelotte.