The 'house of the archives' (Ezr 6:1 RV; AV 'rolls') was a part of the 'treasure house' (Ezr 5:17) of the Persian kings at Babylon, in which important State documents were preserved.
So now, if it seems good to the king, let search be made in the king's store-house at Babylon, to see if it is true that an order was given by Cyrus the king for the building of this house of God at Jerusalem, and let the king send us word of his pleasure in connection with this business.
Then Darius the king gave an order and a search was made in the house of the records, where the things of value were stored up in Babylon.
Basic English, produced by Mr C. K. Ogden of the Orthological Institute - public domain