In the previous chapter, we looked at the beginning of Revelation, which sets up the book as an apocalypse (Rev. 1). Then we discussed the heart of the letter part of Revelation (Rev. 2-3). In the chapter that follows this one, we will look at Revelation 4-11 and other parts of Revelation that give us imagery of the final judgment and victory of God and Christ. In this chapter, we want to look at some of the middle chapters in Revelation.
The imagery of Revelation 12 is not difficult to understand, especially if we can get in mind that the events of Revelation do not all happen in a chronological order. The chapters that come right before have been giving us image after image of the final judgment. But when we get to Revelation 12, we have arrived at the eye of the storm. John pauses for a moment to step back and give us the heavenly story that has gotten us to this point.
The woman with a crown of twelve stars on her head is clearly Israel, with the twelve stars standing for the twelve tribes of Israel. John is a Jew. Assuming that he is John the son of Zebedee, he is not just any Jew. He is a very conservative Christian Jew. Remember in Galatians 2 when Paul appeared before Peter, James, and John. Thy did not force Paul to have his Gentile coworker Titus become circumcised, but the wording of 2:3 makes us think they would have preferred it.
But some of the things John writes in his letters also makes it clear that he does not consider all the Jews of the world to truly be Jews. Some synagogues in his world are rather "synagogues of Satan" (e.g., 2:9; 3:9). We can imagine that John believed Jewish believers to be the true remnant of Israel and that those in these opposing synagogues were not truly Israel at all.
The true Israel stands at the heart of the coming kingdom. On the one hand, John clearly has a place for the Gentiles in the kingdom. After all, there are people there from every "nation, tribe, people, and language" (7:9). But the heart of the kingdom are the 144,000 who were sealed from the twelve tribes, 12,000 from each.  For John, these did not represent all the Jews of the past but the Jews alive in John's day who were currently suffering but eventually going to be saved--true Israel.
And here it is worthwhile to pause and think about what is going on in the book of Revelation. In Revelation, John's time blurs into all time, which blurs into the end time. John is thus both preterist and idealist and futurist all at the same time, like three images all overlaid on each other. The first image is that of John's day and events going on at the time he was writing. But these struggles would become the struggles of all time throughout church history. Yet we believe that there will be a final judgment and Jesus will return to earth. God will set the world to right.
So the woman represents true Israel (12:1). The dragon obviously represents Satan (12:3). He has seven heads which, we will see, represent Rome. The dragon swept a third of the stars out of the sky, which may refer to the angels that "did not keep their positions of authority but abandoned their proper dwelling" (Jude 6). In other words, the verse refers to the fallen angels.
The child to which the woman gives birth is Jesus, the Messiah, destined to rule the world (12:5). He was "snatched up to God and his throne" when he rose from the dead. The woman was now waiting for his return for a season, symbolically represented by 1,260 days. This year and a half period is not literal but represents the current age of persecution, while we are awaiting Christ's return.
It is tempting to see imagery of the early Christian escape from Jerusalem just before the Roman siege of the city. According to an early tradition, the early Christians fled to Pella in keeping with Mark 13:14, which warned Christians to flee to the mountains when they saw the Romans coming to desecrate Jerusalem. Could Revelation 12:13-16 allude to the escape of the Jerusalem church from the city? Meanwhile, the dragon turns to the rest of those in the world who keep God's commands (12:17)...
 We shouldn't think of this as a literal number. It is rather symbolic.