Hi everybody,
first time posting here. Saw that you guys were pretty knowledgeable in history, so you may help me out on this one. I read in some old French sources that, at the end of the 18th century, the Marquisat d'Arlon - markgrafschaft Arel was a possession of the Prussian king. However, I can't seem to find other sources to corroborate this. That would be incredible if it was true, knowing that Arlon-Arel (today part of Belgium) as always been associated to the Duchy of Luxembourg.
Here are the link to my (French-speaking) sources.
https://www.1789-1815.com/belgique_1802.htm (under the "Forêts" entry)
Have a nice day !
PS : English isn't my mother tongue, so sorry if I made mystakes.
I'm not able to provide you with additional sources besides those you provided that entail specific dates and specificity in territory with land possession, but perhaps understanding the reasons that these lands were under disputed ownership would help contextualize this for you.
From 1792 onward, France was at war with Austria and Prussia (later joined by other European powers) in what are invariably known as the French Revolutionary Wars, the War of the First (later Second) Coalition, and then the Napoleonic Wars. This territory was part of the departement of Forêts when France was successfully pushing outside of its borders during the war, and was occupied by the Allied forces (Prussian and Austrian) when they were not doing so well, and the Allies were advancing within or on France's borders. I do not want to speculate on anything, though as you pointed out your sources provided show that these lands were under Prussian authority when they were written.