Messiah (mâšîah, "the anointed one"): Jewish religious concept, a future savior who will, in some sense, come to restore Israel. Both the nature of the Messiah and the restoration were matters of debate.
Dating the coming of the Messiah
According to the popular chronology of the first centuries BCE and CE, the world had attained the age of 5,000 years. Since it was also widely believed that the world would last only 6,000 years (1,000 years for each day of creation), and that the Messiah would reign for 1,000 years before the end of the world, it was evident that he was due to arrive.
One of the most intriguing attempts to date his coming more precisely, can be found in the First book of Enoch, a complex five-book text that was composed between the third century BCE and the first half of the first century CE. The first part, known as the Book of the watchers and written in the third century BCE, gives a description of the patriarch Enoch's visions of heaven. In chapter 10, the author tells:
And when they [the fallen angels] and all their children have battled with each other, and when they have seen the destruction of their beloved ones, bind them for seventy generations underneath the rocks of the ground until the day of their judgment and of their consummation, until the eternal judgment is concluded.note[1 Enoch 10.12.]
The implication is that there are seventy generations from Enoch until the Day of Judgment (or seventy-seven generations from the Creation, since Enoch is a member of the sixth generation since Adam). The First Book of Enoch was well-known to the Jews and the Jewish Christians.note[There is an allusion in the Epistle of Jude 14.] In the Gospel of Luke, this traditional chronology was accepted, but slightly modified. (Go here for a comparison.)
The model of all this must have been Daniel 9.24-27, which mentions the coming of the Messiah, the prince (nasi), seven "weeks" (of seven years each) after God's order to restore Jerusalem. According to Jeremiah 30.18, this order was issued in 587 BCE; as a consequence, we can identify this Messiah with Cyrus.
Seventy weeks of years are decreed concerning your people and your holy city, to finish the transgression, to put an end to sin, and to atone for iniquity, to bring in everlasting righteousness, to seal both vision and prophet, and to anoint a most holy place.
Know therefore and understand that from the going forth of the word to restore and build Jerusalem to the coming of a Messiah, a prince, there shall be seven weeks. Then for sixty-two weeks it shall be built again with squares and moat, but in a troubled time.
And after the sixty-two weeks, a Messiah shall be cut off, and shall have nothing; and the people of the prince who is to come shall destroy the city and the sanctuary. Its end shall come with a flood, and to the end there shall be war; desolations are decreed.
And he shall make a treaty with many for one week; and for half of the week he shall cause sacrifice and offering to cease; and upon the wing of abominations shall come one who makes desolate, until the decreed end is poured out on the desolation.
The rest of the prophecy is a bit harder to interpret. It is very tempting to interpret the second Messiah with Onias, a high-priest that was killed in 171 BCE, and the destruction of the sanctuary with the persecution led by Antiochus IV Epiphanes (above), which indeed lasted "half a week" (three and a half years). The problem that between the return from the Babylonian Captivity and the killing of Onias no "sixty-two weeks" had passed, is not unsurpassable. Chronologies like these are more often than not inaccurate.