Willem was the son of King Willem II and Anna Paylovna of Russia and on the death of his father in 1849, he succeeded as king of the Netherlands where ruled until his death in 1890.
William III was a man of immense stature with a boisterous voice, standing at 6’5″ (196 cm) he was an exceptionally large and strong man. Known to be a philanderer he had several dozen illegitimate children from various mistresses. He could be gentle and kind, then suddenly he could become intimidating and even violent. He was inclined to terrorize and humiliate his courtiers and servants. His ministers were afraid of him and most people around him agreed that he was, to some degree, insane.
He married his first cousin, Sophie, daughter of King William I of Württemberg and Grand Duchess Catherine Pavlovna of Russia on 18 June 1839. This marriage was unhappy and was characterized by struggles about their children. Sophie was a liberal intellectual, hating everything leaning toward dictatorship, such as the army. Whereas William was simpler, more conservative, and loved the military. His extramarital enthusiasms, however, led the New York Times to call him “the greatest debaucher of the age”. Another cause of marital tension (and later political tension) was his capriciousness as he could rage against someone one day and be extremely polite the next.