William I of the Netherlands, also known as William of Orange, was the first King of the Netherlands, reigning from 1815 to 1840. He played a crucial role in the establishment of the modern Dutch state after the defeat of Napoleon. His leadership helped unify the northern and southern provinces, leading to the formation of the Kingdom of the Netherlands. During his reign, William I focused on economic development and modernization, promoting infrastructure projects and industrial growth. He also faced challenges, including tensions between the northern and southern regions, which eventually contributed to the separation of Belgium from the Netherlands in 1830.