Paul V. also mentions (in his inscription at the fountain above S. Pietro in Montorio) that it had been previously restored by one of his predecessors, Hadrian I., A.D. 774. This was after it had been damaged by the Lombards under Astulfus, as recorded in the Pontifical Registers of Stephen III., Hadrian I., and Gregory IV., in whose time (A.D. 830) the work was completed. The Saracens again destroyed it in 846, and it was again restored by Nicholas I. (A.D. 860). It continued in use in the fifteenth century; but in the sixteenth it was much out of repair, and the branch to the Janiculum almost entirely failed. That to the Vatican continued to flow in 1561, and was repaired by Pius IV., as recorded on an inscription in the garden of the Vatican. In 1618, it had become almost entirely ruined, and was restored in a more thorough manner at great expense by Paul V., a member of the wealthy Borghese family, from whom it is now commonly called the Aqua Paola. The Orsini family, to whom the lake Bracciano belonged, contributed 2,000 ounces of water daily from that lake. Hadrian I., who had made the first great restoration of this water-course, was a Colonna, so that three of the greatest medieval families of Rome have contributed towards it. The cascade which now falls down the face of the Janiculum, in a _specus_, turns the water-wheels of three mills in its course; this is mentioned by Procopius, they having been destroyed by the Goths, and their place supplied by other mills made in the Tiber by Belisarius, which continued in use for a long period. The ruins still visible in the river, opposite the mouth of the Cloaca Maxima, are supposed by some to have belonged to these mills. They were of wood only[168], and may have been built on the stone foundations; but these ruins in the river more probably belonged to the fortifications at the head of the Port of Rome, where there was a chain across the river to prevent boats from being carried down by the rapid stream into the Port[169].