The brook which runs at the bottom of the northern valley (Fosso dell’ Acqua Ferrata) has received the name of the Peneius from antiquaries, and that in the southern valley is called Fosso di Risicoli by the modern inhabitants. These streams are now very scantily supplied with water, but in ancient times, when the villa was watered by a constant flow from its aqueducts, they must have been of considerable volume. The ruins, now overgrown with clumps of cypress and other trees, extend for a space of seven miles in circumference, and in the middle ages were known as Tivoli Vecchio, from a vague and unfounded idea that the ancient city of Tibur stood here. It has been remarked that the Coliseum is strikingly characteristic of the Flavian emperors who planned and executed it, and with equal truth it may be said that the Tiburtinum of Hadrian gives a marvellous picture of the many-sided genius of the great man who was at once the ruler of the whole known world and had travelled throughout his vast domains from Britain to the Euphrates, organising and controlling everywhere, and at the same time showing an appreciation of and value for literature, philosophy, and the fine arts, which was generally foreign to the Roman character. Hadrian constructed in his villa at Tibur a panorama of all the sights which had struck him most in his world-wide travels, in order that he might in this realm of enchantment, when no longer able to travel, have the sights and thoughts in which he had taken such pleasure, revived for his imagination to feed upon. Considering the size and magnificence of the place, which almost resembles a town in its vast extent, it is surprising that so few notices of it should be found among the Roman historians and biographers. Dion Cassius, or rather his epitomiser Xiphilinus, does not even mention it, and Spartianus and Aurelius Victor pass it over without such special remark as we should expect. As, however, a great part of the building consisted of the familiar Thermæ, stadia, theatres and gymnasium, which were constructed in every large Roman villa, they were perhaps not noticed, as matters of course, and only the peculiarities of the villa were recorded. After Hadrian’s return to Rome at the end of his last journey to the East in A.D. 135, he resigned the care of the empire to Lucius Ælius Verus and retired to this villa, which had probably been built during his absence, and may have been begun in 125 when he returned to Rome from his first journey, and finished during the last three years of his life from 135 to 138. This opinion as to the date at which the villa was built is confirmed by the stamps found on the bricks, which range from the year 123 to the year A.D. 137, and that the ruins belong to Hadrian’s villa is sufficiently attested by universal tradition, and by the number of statues of Antinous, and other works of art found here unquestionably belonging to the reign of Hadrian.