Agorin revealed that the relics of Minas Gîl have been irreversibly corrupted by the sorcerers of Dol Guldur.
'There is no other way, ${PLAYER}: while it pains me more than anything to order it so, any Elven relics remaining within Minas Gîl must be destroyed...and quickly! Their purpose has been corrupted beyond recovery, and the powers they now shape at the hands of the Enemy are too dangerous to be left unchecked.
'Return to Minas Gîl and destroy these artifacts wherever you find them within, so that they are of no further use to our enemies.
'In the meantime, I shall attempt to divine who or what has brought about this evil deed, so that we may have our vengeance upon them for this grievous loss.'
The corrupted relics lie within Minas Gîl, east of Ost Galadh.
Agorin has asked you to destroy the corrupted Silvan relics within Minas Gîl.
Agorin is at Ost Galadh, west of Minas Gîl.
You should report your success to Agorin.