A brief commentary on this post.
If there are 1000 years for the Sitra Achra to reign, we can look at 1000 year histories starting at the beginning of Galus.
It would seem that the earliest date to examine would be the time of the cessation of the Tamid, 3157.
3157 + 1000 = 4157 - 3760 = 397CE. This is 2 years after the split in the Roman Empire in to 2.
The later time for the start of the 1000 years of Galus would be Galus Edom's start, 3830.
3830 + 1000 = 4830 - 3760 = 1070CE.
This is 1 year before the Battle of Manzikert, described here as the immediate cause of the Crusades.