The 1000-Year Sale
In the Perasha, Yaakov Avinu asks Eisav to sell him the first-born rights. Bereishit Rabba 63:13 adds that he also requested something else in this sale:
ויאמר יעקב מכרה כיום אמר לו זבין לי חד יום מן דידך אמר רבי אחא כל מי שהוא יודע לחשב ימי הגלות ימצא שיום אחד ישב יעקב בשלוה בצלו של עשוAnd Yaakov said, "Sell like the day" - He [Yaakov] said to him [Eisav], "Sell me 1 day of yours." Ribbi Aha said, "Anyone who knows how to calculate the days of exile will find that Yaakov sat 1 day in tranquility in the shadow of Eisav."
This means that the Jewish people were at peace from Eisav for a period of "1 day".
The concept of "1 day" is undisputed - it refers to 1000 years, as we know from the verse כי אלף שנים בעיניך כיום אתמול כי יעבר. What is in dispute, however, is when these 1000 years took place.
The Eitz Yosef quotes the נזה"ק who says that you find the 1000 years from Yitziat Mitzraim until the "Shi'bud" of the 2nd Beit Hamikdash started (presumably subtracting the 70 years of Galut Bavel). The issue with this is - can you really consider this "in the shadow of Eisav"??
Other commentators seem to say that it started when Galut Edom started. The problem with this is that it's hard to find 1000-years worth of peaceful times.
According to the second opinion, Ribbi Aha is making a prediction for the future - not a statement of the past. This may even fit better with the wording of "לחשב ימי הגלות".
If anyone has any insights in this, I'd much appreciate them.