 In 1816, Wiesweiler passed to the Principality of Lichtenberg, a newly created exclave of the Duchy of Saxe-Coburg-Saalfeld, which as of 1826 became the Duchy of Saxe-Coburg and Gotha.As part of this state, it passed in 1834 to the Kingdom of Prussia, which made this area into the Sankt Wendel district.Later, after the First World War, the Treaty of Versailles stipulated, among other things, that 26 of the Sankt Wendel district's 94 municipalities had to be ceded to the British- and French-occupied Saarland.