The less civilised and more distant tribes were not, like these, subject to regular tribute, but each time the sovereign traversed their territory or approached within reasonable distance, their chiefs sent or brought to him valuable presents as fresh pledges of their loyalty. Royal outposts, built at regular intervals and carefully fortified, secured the fulfilment of these obligations, and served as depots for storing the commodities collected by the royal officials; such outposts were, Damdamusa on the north-west of the Kashiari range, Tushkhan on the Tigris, Tilluli between the Supnat and the Euphrates, Aribua among the Patina, and others scattered irregularly between the Greater and Lesser Zab, on the Khabur, and also in Nairi. These strongholds served as places of refuge for the residents and their guards in case of a revolt, and as food-depots for the armies in the event of war bringing them into their neighbourhood. In addition to these, Assur-nazir-pal also strengthened the defences of Assyria proper by building fortresses at the points most open to attack; he repaired or completed the defences of Kaksi, to command the plain between the Greater and Lesser Zab and the Tigris; he rebuilt the castles or towers which guarded the river-fords and the entrances to the valleys of the Gebel Makhlub, and erected at Calah the fortified palace which his successors continued to inhabit for the ensuing five hundred years. Assur-nazir-pal had resided at Nineveh from the time of his accession to the throne; from thence he had set out on four successive campaigns, and thither he had returned at the head of his triumphant troops, there he had received the kings who came to pay him homage, and the governors who implored his help against foreign attacks; thither he had sent rebel chiefs, and there, after they had marched in ignominy through the streets, he had put them to torture and to death before the eyes of the crowd, and their skins were perchance still hanging nailed to the battlements when he decided to change the seat of his capital. The ancient capital no longer suited his present state as a conqueror; the accommodation was too restricted, the decoration too poor, and probably the number of apartments was insufficient to house the troops of women and slaves brought back from his wars by its royal master. Built on the very bank of the Tebilti, one of the tributaries of the Khusur, and hemmed in by three temples, there was no possibility of its enlargement--a difficulty which often occurs in ancient cities. The necessary space for new buildings could only have been obtained by altering the course of the stream, and sacrificing a large part of the adjoining quarters of the city: Assur-nazir-pal therefore preferred to abandon the place and to select a new site where he would have ample space at his disposal. [Illustration: 067.jpg THE MOUNDS OF CALAH]