The Zohar is one of the great mysteries of Jewish history. The secrets contained in it are beyond the imagination of most. The Zohar, aside from other issues, engages in giving down prophecies related to the End of Days. The fascinating thing is how it conceals itself.
One of the more well-known prophecies/predictions relates to 100 years of Galus for each of the 12 tribes, or 1200 years total. This shows up in multiple places in the Zohar.
The Zohar is written in a way to immediately discredit itself. If there are 1200 years of Galus after the destruction of the Beit HaMikdash in the year 3828 (68CE), that brings us to the year 5028 (1268CE). This is approximately the time that the Zohar was revealed. This interpretation of the calculation is brought by many an academic as backing up the claim that the Zohar is of 13th century origin. By itself, it seems like convincing evidence.
However, 1200 is not the only number mentioned in the Zohar.
- The Zohar Chadash on Mechirat Yosef (The Sale of Joseph by his brothers) says that Yosef was away from his father for 22 years, multiply this by 7 per the verse "seven for your sins" (from Bechukotai), and multiply by 10 for the 10 brothers that sold Yosef, and you end up with 1540 years after the destruction by Esav in the year 68CE. We are now in the year 1608CE. This is mentioned in context with Moshiach ben Yosef.
- The Zohar part 1 on Parshat VaYera mentions explicitly the year 5600 (1840CE) in a messianic context of when upper and lower wisdom would be bestowed.
- The Zohar part 1 on Parshat Toldot mentions the year 5408 (1648CE) in a messianic context as well.
It is fairly obvious from adding all these together that the writers of the Zohar did not believe that Moshiach was absolutely going to come in the 13th century, but rather some centuries after that.
Perhaps that is part of the secret of why the Zohar was revealed when it was.