I grew up on apple, rhubarb, and peach crumble (not all in the same dish, except for the first two, sometimes) and my mother claims she used the recipe from the old Be-Ro cookbook, published in the 1920s. (Be-Ro was a brand of flour.) I also grew up using this cookbook for cakes and pancakes, etc.
The crumble recipe called for rubbing in the fat and flour, then adding sugar, and baking it as a topping on stewed apple. Over the years we modified it a bit, such as adding oats or desiccated coconut, using crunchy raw sugar instead of white or soft brown, and using half self-raising flour to add some texture.