The late King of the Belgians, Leopold of Saxe-Coburg, 1865. Leopold I (1790-1865) was the first King of the Belgians, reigning from 21 July 1831 until his death in 1865. Leopold took a commission in the Imperial Russian Army and fought against Napoleon after French troops overran Saxe-Coburg during the Napoleonic Wars. After Napoleons defeat, Leopold moved to the United Kingdom, where in 1816 he married Princess Charlotte of Wales. In 1831 he accepted the throne of Belgium following the countrys independence in 1830. From "Illustrated London News", 1865.