The least pure, however, before the time of Trajan, were the Anio Vetus and Anio Novus. This arose from the banks which, being soft, gave way, and the stream, even in fair weather, thus became muddy. He points out that hitherto, by the mixture of the waters which had been adopted to prevent failure in supply, proper skill had not been shewn, and these new streams were allowed to destroy the purity of others[162]. His object, therefore, was to keep the pure streams separate, and in addition to that, arrange that they should be used for drinking purposes only; while the water which was less grateful to the taste, and which was subject to be at times muddy, should be used for cleansing the city, or watering the gardens, or other ordinary purposes, which it might fulfil equally with the fresher and purer water. In considering the supply of water to our large towns, which is one of the great problems which at the present time has to be solved, it is not too much to say that—the plan adopted by the Emperor Trajan, by the advice of Frontinus, the head of the _aquarii_, and of that department of the government of Rome which had charge of the aqueducts, the importance of which in that climate can hardly be over-estimated—is worthy of more attention than it has received[163]. THE CURATOR AQUARUM. The care of the aqueducts was assigned by Augustus to a Curator Aquarum, of whom Marcus Agrippa was the first, and held the office for life. Frontinus, to whom we are indebted (as we have seen) for nearly all that we know respecting the early history of the aqueducts, held this office under Domitian, A.D. 94; he remained in office under Nerva, wrote his treatise at that time, and died under Trajan, A.D. 107. The office continued to exist till the third century, in the time of Diocletian, when it was superseded by the magistrates called _Consulares Aquarum_, a title changed in the fifth century into _Comes Formarum Urbis_. These several magistrates had 700 servants, charged with the superintendence, repair, and distribution of the water from the aqueducts, divided into _familia publica_ and _familia Cæsaris_; the former, comprising 240 persons paid by the State; the latter, 460 paid by the Emperor. Agrippa supplied the city with 700 _lacus_, 105 fountains, 130 _castella_ for distributing waters, and 170 gratuitous baths for public use. These structures were adorned with 400 marble columns, and 300 statues of marble or bronze. After the devastations caused in the Gothic wars, under Vitiges and Totila, only the most important aqueducts were restored, either by Belisarius or Narses. Ruin and neglect again undid much of what had then been restored to use. At the beginning of the ninth century, the only aqueducts supplying water were the Appian [I.], and Marcian [XII.], then called Jobia or Iopia, by corruption from “Jovius,” the name assumed by Diocletian.