Throughout its history, the size of Jerusalem expanded, but also diminished at times. The city began its history on the Eastern Hill, located between the Kedron and Central Valleys. That is where Salem, the city of Melchizedek was located. The Jebusites took over the city and built a strong fortification around the Gihon Spring to the east. King David captured the Jebusite city and since then it is called the City of David. His son Solomon built a new Temple on Mount Moriah, to the north of the City of David and joined the new Temple complex to the previous city with city walls. Jerusalem was greatly enlarged by King Hezekiah who had to cope with a large influx of refugees from the Assyrian invasion. For the first time in its history, the Western Hill was enclosed with city walls and joined to the City of Solomon. Josephus called this new city wall the First Wall.
After the Babylonian Exile, Jerusalem was restored, but the Western Hill was left out. It was in the Hellenistic period that this hill became part of Jerusalem again. King Herod the Great enlarged the city to the north, as far as the present-day Damascus Gate. This new wall was called the Second Wall. Just before the revolt against the Romans, an attempt was made to build another wall further to the north, the Third Wall. It is unclear if this wall was ever completed. In the Byzantine period, new city walls were built to replaced the destroyed Herodian walls. The present-day northern wall of the Old City follows the line of the Byzantine wall.