These are stunning blueish grey wool riding breeches from Italy. I am not a military uniform expert, but according to my research they are most likely from the 1930s and would have been used while riding a motorcycle or a horse. They have both hip pockets and front pockets, as well as back pockets. They do not have any tags or markings apart from the writing on the buttons "Unione Militare".

32" waist
27" inseam
5.5" leg openening (when pressed flat; tie closures)
13" rise