Before describing in detail these, by far the most complete and interesting Celtiberian remains in the Peninsula, a few words may be said with regard to the discovery and exploration of them, as well as to the theories as to their origin. For reasons which need not be re-stated here the Celtic element was less intimately mixed with the Iberian in the north-western part of the Peninsula than elsewhere, and the tribes in this part of the country were those which withstood longest the imposition of the Roman bureaucratic system after the assassination of the patriot Viriatus, and the fall of Numancia in the second century B.C. Not till the time of the great Julius did the legionaries, stationed then permanently at Braga, sweep all this province clean of revolt, and bring the tribesmen to their knees after dire slaughter and destruction. The Celtiberian tribes in this remote corner had lived their simple pastoral lives from time unrecorded in small family clans, each independent, with its own law and its own gods; but for purposes of mutual defence in later times confederations of many clans were formed, _mòr thuatha_, as in Ireland. Each of these confederations possessed a fortified centre or stronghold as a place of assembly and refuge, usually upon an eminence, wherein the scattered clans might meet for defence or in council to treat of common interests. The Roman historian, Valerius Maximus speaks especially of some such fortress upon a mountain in Lusitania, and praises its inhabitants for their stubborn bravery. He calls it by the name of Citania, and antiquaries have given to the extensive ruins now before us that name during the last few years, on the assumption that this may be the place referred to by the Roman chronicler. Vague stories had always pervaded the countryside of buried ruins, with the accompanying legends of witches, warlocks, and enchanted Moors existing upon the hill of São Romão; and in the eighteenth century the curate of São Estevão de Briteiros at the foot of the hill had brought down from the hill-top and placed in his church porch a great mysterious slab of stone covered with mystic devices and of strange fashioning. But not until our own times did a man come with public spirit enough to devote his life and small fortune to the exploration of this city of the past, for in Portugal public encouragement of any such objects is rare indeed. This man was Dr. Sarmento, who for many years until his death recently, made a labour of love in uncovering systematically the vestiges of the prehistoric city.