According to Kabbalah, the development of Z"A is broken up in to stages:
- Ibbur (Pregnancy)
- Yenikah (Suckling/Nursing)
- Katnut (Childhood)
- Gadlut (Adulthood)
In Shiur Yemot HaMoshiach, I mentioned the idea of Gadlut. I'd like to look at Ibbur.
It is brought in Pitchei She'arim (part 2, page 56) that the period of Ibbur started with the birth of Avraham Avinu (1948), and ended with Yetziat Mitzraim (2448).
Specifically, there are:
- The first 3 days, corresponding to Avraham, Yitzchak and Yaakov.
- The next 37 days, corresponding to the 12 tribes and the 70 souls that went in to Mitzraim
- The remaining 7 months of pregnancy, corresponding to the 210 years in Mitzraim. (This time period is explicit in the text)
I would propose that the first 3 days were from the birth of Avraham until just after the birth of Yosef, when Yaakov decides to leave Lavan and go back to Eretz Yisrael. This would leave 84 years per "day". By mathematical default, that would also leave 1 year per "day" for the the 37 days. This (at this point) is my hypothesis.
Regardless, it was after 500 years that the birth occurred, both in the upper and lower worlds. This is what we celebrated last night.