United Kingdom of the Netherlands
The name used to refer to a new unified European state created during the Congress of Vienna in 1815. This state, also often called simply "Kingdom of the Netherlands", was made up of the former Austrian Netherlands to the south and the former United Provinces to the north.
The intention was to provide a viable state to the north of France to counterbalance potential new French ambitions in this direction. It lasted until the southern provinces seceded to form Belgium in 1830, though Belgian independence was not formally recognised by the north until 1839, after which the name "Kingdom of the Netherlands" remained to refer to just the northern provinces.