Introduction to the Proofs of the Evidence:

To reasonably prove something, one must show that something is true or at least that no other conclusion can be reached. This may also involve showing that all alternatives are false, leaving the proposed alternative as the only possible answer (a method that does not always lead to the right answer because authors sometimes fail to consider all alternatives). Several methods show the date 457 B.C. is the correct date for the decree that fulfills the prophecy of Daniel 9.  For the author's purposes, the following methods are used:

(1) We can start from the beginning of the 70-weeks of years and demonstrate it is very likely true by showing that the terminating event of the first 69-weeks of years did in fact happen as predicted. The conclusion would be that the starting date is right if the correct ending event occurs when predicted.

(2) Working backwards, we can show that the 457 B.C. decree is the only one that fits the specific time range.

(3) We can find a recorded marker event, (which we can roughly date to the year,) inside of the 70-weeks that is only known by those involved if 457 B.C. is the correct starting date,

(4) Or finally, we can show that decree issued in 457 B.C. fulfills the prophecy by analyzing the language of the prophecy.

All proofs, unless otherwise stated, assume all actual measurements of the length of a year by using a solar year. This is logical given that in the section about why 444 B.C. is not a valid date for starting the 70-week prophecy, we explain how using 457 B.C., as the starting date requires using solar years for measuring the length of the year. A solar year is the actual time for a complete rotation of the earth around the sun. Currently a complete rotation takes 365.2422 days. This is a reasonable approach because there is no indication that God intended people to measure the length of the year according to the prophetic "time" (or "times") as is given in Daniel 7:25 (360 days). The time or times of Daniel 7:25, the 1260 days of Revelation 12 and 13, and the 42 months of Revelation 13 are based on the idea of counting how many years were to occur, and are not determined by the definition of the length of an actual year. When we carefully read the context this becomes very clear.

God gives a definition of the prophetic month so that we would know how to count the number of years. Now that is strange, if you think about it, because if the Jews used only 30-day months (which some claim they did, but in fact they did not), WHY would God need to define the month as 30 days in length? Something to think about, is it not?

Unfortunately, there are those who seem to think that because the months of prophetic time are 30 days, then the literal solar year itself then must consist of 12 months of 30 days each. This is false because God knows how long the actual year is. In addition, there is no evidence from history supporting the idea that there were 12 months of 30 days each in Jewish culture and science. The Jews did not use 30-day months exclusively either in spite of what some web sites claim. To the contrary, the Jewish year consisted of 29 and 30-day months that alternated, and then added additional months in to correct for drift of the calendar away from the cycles of nature and the true date. Over a period of 19-year cycles, it worked fairly well to keep the calendar lined up with the cycles of nature. Therefore, their actual year did average out to being reasonably close to the number of actual days in a year.

One other problem with the use of a 30-day month to define the length of the year is that the 30-day month is symbolic of time. Each day stood for a year. Therefore, the 30-day month is a symbol and therefore very unlikely to be based on real months that an ancient culture used.

On this web page, the author uses the term "proof" to "prove" that the date 457 B.C. is the correct starting date.   Perhaps this term should have been "arguments in favor" of 457 B.C. because it is just not possible to "prove" the date absolutely.   However, the evidence in favor of 457 B.C. is very strong. You will have to judge for yourself if the arguments are valid and true.