Twenty miles to the south of Sidon was the still more important city--the double city--of Tzur or Tyre. Tzur signifies “a rock,” and at this point of the Syrian coast (Lat. 33º 17´) there lay at a short distance from the shore a set of rocky islets, on the largest of which the original city seems to have been built. Indentations are so rare and so shallow along this coast, that a maritime people naturally looked out for littoral islands, as affording under the circumstances the best protection against boisterous winds; and, as in the north Aradus was early seized and occupied by Phoenician settlers, so in the south the rock, which became the heart of Tyre, was seized, fortified, covered with buildings, and converted from a bare stony eminence into a town. At the same time, or not much later, a second town grew up on the mainland opposite the isle; and the two together were long regarded as constituting a single city. After the time of Alexander the continental town went to decay; and the name of Palæ-Tyrus was given to it,[415] to distinguish it from the still flourishing city on the island. The islands of which we have spoken formed a chain running nearly in parallel to the coast. They were some eleven or twelve in number. The southern extremity of the chain was formed by three, the northern by seven, small islets.[416] Intermediate between these lay two islands of superior size, which were ultimately converted into one by filling up the channel between them. A further enlargement was effected by means of substructions thrown out into the sea, probably on two sides, towards the east and towards the south. By these means an area was produced sufficient for the site of a considerable town. Pliny estimated the circumference of the island Tyre at twenty-two stades,[417] or somewhat more than two miles and a half. Modern measurements make the actual present area one of above 600,000 square yards.[418] The shape was an irregular trapezium, 1,400 yards along its western face, 800 yards along its southern one, 600 along the face towards the east, and rather more along the face towards the north-east.