It is essential that we know an accurate chronology of the books of Ezra and Nehemiah, if we are to understand the fulfillment of the Seventy Weeks Prophecy in Daniel. In my own opinion we have allowed the world to interpret for us the time frame of these books and those that relate to them, namely Esther, Haggai, Zechariah and Malachi. Once we begin to try to fit the events of the Bible into the historical chronology prescribed for the nations surrounding Israel, we build for ourselves a labyrinth out of which there is no path without denying the word of God or creating an historical puzzle with missing pieces and questionable content.
Brethren we ought not to seek the approval of the world. This is a trap (Micah 2:11; Luke 6:26; John 7:7). Their minds are corrupt as far as their understanding of God and his work is concerned (2Timothy 3:1-9), as was our own before we began our walk with him. We are anointed of God to be lights to this world. We cannot be hid, because Christ has made it so (Matthew 6:14; cp. 1Timothy 5:25). Even if we err concerning chronology, the world will take note and be among the first to point it out and accuse us of being purveyors of myth, yet they cannot agree among themselves concerning the age of the earth or the age of anything in the universe for that matter. They throw around millions and billions of years as though it were only a few weeks or months, never considering the scientific consequences of having a universe as old as they claim. As far as recorded history is concerned, we have a kind of variety pack of pick your own chronology.
The problem with chronology is there is more than one opinion concerning the length of time between one period and another or whether or not one period overlaps another and, if so, by how much. For example, the chronologies of the Pharaohs of Egypt cannot be used as a litmus test for chronological accuracy. None of what is known can be set in stone as far as when it occurred is concerned. It seems that dynasties are sometimes taken from one age and placed in another to please some new information that had been found. A case in point involves the 26th dynasty, which if taken by itself would deny that either Nebuchadnezzar or Cyrus the Great had ever risen to power and conquered Egypt. According to some Egyptologists, the Saite or 26th dynasty (664-525 B.C.) leaves no room for either Nebuchadnezzar’s or Cyrus’s exploits. This creates an error in ancient chronology of more than a century, and at a critical time frame for dating the captivity of Jerusalem by Nebuchadnezzar and the release of the Jews from Babylon by Cyrus. The proposal is that the 26th and 27th dynasties, 139 years and 121 years respectively, should run parallel rather than successively, and previous dynasties brought forward to replace the gap vacated by the 26th dynasty. This would not help my case for proving that Nebuchadnezzar and Cyrus came approximately 79 years later than historians wish to date them, but it does show that much more thought needs to be given to ancient chronology and that some placement of the ancient kings is more arbitrary than factual.
 Easton’s Bible Dictionary: “Chronology is the arrangement of facts and events in the order of time. The writers of the Bible themselves do not adopt any standard era according to which they date events. Sometimes the years are reckoned, e.g., from the time of the Exodus (Num. 1:1; 33:38; 1 Kings 6:1), and sometimes from the accession of kings (1 Kings 15:1, 9, 25, 33, etc.), and sometimes again from the return from Exile (Ezra 3:8). Hence in constructing a system of Biblical chronology, the plan has been adopted of reckoning the years from the ages of the patriarchs before the birth of their first-born sons for the period from the Creation to Abraham. After this period other data are to be taken into account in determining the relative sequence of events…”
“To show at a glance the different ideas of the date of the creation, it may be interesting to note the following: From Creation to 2000: According to Ussher, 6004; Hales, 7,411; Zunz (Hebrew reckoning), 5,988; Septuagint (Perowne), 7,411; Rabbinical, 5,760; Panodorus, 7,493; Anianus, 7,501; Constantinopolitan, 7,509; Eusebius, 7,199; Scaliger, 5,950; Dionysius (from whom we take our Christian era), 7,494; Maximus, 7,501; Syncellus and Theophanes, 7,501; Julius Africanus, 7,501; Jackson, 7,426.” (I have updated the year of reckoning to creation in Easton’s Bible dictionary from 1894 to the year 2000 A.D.)
 See Centuries of Darkness (1991) by Peter James and A Test of Time (U.S.A. Pharaohs And Kings (1995)) by David Rohl. Also see Ages in Chaos by Immanuel Velikovsky who also rearranges the Egyptian dynasties to better accommodate the histories of other nations in the Middle East.