Dragon burial mound north of Harmugstahl. The sword is stuck in a tree with a helm resting on its hilt. The sword can disappear very fast, so if you don't see it, load a previous save and approach the place again. There is a knapsack under the sword that doesn't disappear.

If you can see it, but not pick it up, try using: prid XX0853A6 disable enable


Dragon burial mound north of Harmugstahl