To most Israelis it is axiomatic that the celebrations for the 3,000th anniversary of the conquest of Jerusalem by King David mark a real and tangible event; but this is far from certain. The biblical account of the capture of the city is the only one we have, and in the opinion of most modern scholars, the Bible is not an entirely reliable historical document. Corroborating evidence is required, and some indeed exists; but it is not conclusive. When all the available information has been assembled, the most that can be said is that there was probably an Israelite ruler called David, who made Jerusalem his capital sometime in the tenth century bce. However, the precise date cannot be determined, and consequently there is no way of knowing exactly when the anniversary falls.
There is plenty of evidence for the existence of ancient Jerusalem. Excavations in the City of David, today the village of Silwan, just south of the Old City walls, show that the site has been continuously occupied for some 5,000 years. Closer to David's purported time, excavations directed by the late Prof. Yigal Shiloh, uncovered a monumental 20 metre stepped structure, and dated it to the 12th-10th century bce. This could have been the foundation of the Jebusite stronghold, captured and subsequently expanded by David.
In addition to the archaeological evidence, Jerusalem appears in several ancient documents, apart from the Bible. The earliest known reference dates to 1900 bce in the so-called "Execration Texts." The names of the enemies of the Egyptian ruler were inscribed on pottery, which was then smashed in the hope of bringing destruction upon them. Jerusalem at that time was apparently an enemy of Egypt, as indicated by letters written on clay tablets found in the ruins of Amarna, the palace of the reforming Pharaoh Akhnetan. In one of them, dating to the 14th century bce, Abdu-Heba, the king of Jerusalem, writes pledging his loyalty to the Egyptian ruler.
Until very recently, there was no evidence outside the Bible for the existence of King David. There are no references to him in Egyptian, Syrian or Assyrian documents of the time, and the many archaeological digs in the City of David failed to turn up so much as a mention of his name. Then, on July 21, 1993, a team of archaeologists led by Prof. Avraham Biran, excavating Tel Dan in the northern Galilee, found a triangular piece of basalt rock, measuring 23 x 36 cm. inscribed in Aramaic. It was subsequently identified as part of a victory pillar erected by the king of Syria and later smashed by an Israelite ruler. The inscription, which dates to the ninth century bce, that is to say, about a century after David was thought to have ruled Israel, includes the words Beit David ("House" or "Dynasty" of David"). It is the first near-contemporaneous reference to David ever found. It is not conclusive; but it does strongly indicate that a king called David established a dynasty in Israel during the relevant period.
(http://www.mfa.gov.il/MFA/MFAArchive/20 ... %20Reality