When was the decree to restore and rebuild Jerusalem issued?
This is somewhat debatable, as there are at least three “decrees” in the Book of Ezra. The first is in Ezra 1:1-4. This is a decree of Cyrus that the Jews can go back to Judah and Jerusalem and rebuild the temple. This decree is from about 537 BC. There is no mention of building the city, and especially of rebuilding the wall, which is almost the definition of a city back then, so this is probably not what the prophecy is a reference to.
The second “decree” is that of Darius in Ezra 6:1-12. This comes from about 518 BC. It is essentially a renewal of Cyrus’ decree to rebuild the temple, and for the same reasons as above, this is probably not what the prophecy in Daniel 9 about a decree to restore and rebuild Jerusalem is referring to.
The third “decree” in Ezra is that of Artaxerxes in Ezra 7:11-28. This is a decree to actually rebuild the city. The decree comes from the seventh year of Artaxerxes (Ezra 7:8). This is somewhere around 458 BC from what we know of Artaxerxes’ reign from outside sources. This decree actually resulted in the rebuilding of Jerusalem under Nehemiah.
Some list a fourth decree based on what is recorded in Nehemiah 1. There is no actual printed decree mentioned here, but we can probably assume that Nehemiah was given some sort of orders and this could be interpreted as a decree. It is more difficult to date these events. It came in “the twentieth year,” but we are not sure exactly what it is the twentieth year of. If it is the twentieth year of Artaxerxe’s reign, then it is around 449 BC or so.
To me, the most likely thing that the prophecy of a decree to restore and rebuild Jerusalem is a reference to is the decree in Ezra 7:11-28, although I will admit that this is somewhat debatable. It just so happens that almost exactly 490 years after this decree (the seventy sevens of Daniel 9:24), Jesus did come to Jerusalem and was killed “to atone for wickedness, to bring in everlasting righteousness, to seal up vision and prophecy and to anoint the Messiah.” (Daniel 9:24). The most likely date of the execution and resurrection of Jesus is AD 30. This is very strong evidence, not only that the Bible is inspired by God, but that Jesus is the Messiah.
For your information, some use the fourth decree in about 449 BC and use the lunar 360 day year and also arrive at an appropriate date for the death of Jesus. I do not agree, but I find the alternative calculation interesting. All this is in my book, Daniel, Prophet to the Nations, available at www.ipibooks.com