Is there any large shield artifact known? Aten's shield is undefined and cyclops' eye is small shield.
Update: Aten's shield is a large shield. Scrolls needed are Champion's Notes.
However there's a report that Aten's Shield scrolls (named Aten's Shield 3 of3) drop off centaurs. Eh whatever -- I hate this thing already, with Vengie help I'm up to about 300 chests now.