Continuing from the last post.
There are some calculations given.
At Har Sinai, a voice went out and said "In this Yovel year you shall return, a man to his inheritance". In 1938 years after Churban HaBayit, each man will return to his inheritance, and the year after those years is the Great Yovel...
... the explanation of this is that the year of the Yovel is the 48th Yovel...
... come and see that the holy nation counted 59 Shmitah years when the Beit HaMikdash arose, and when it was destroyed, they ceased to count, and until the time of the Redemption is 277 Shmitah years that aren't counted, in the secret of "is it not revealed to me..." (Devarim 32:34)
Let's start on the last paragraph. We should just look at these 59 Shmitah years.
Per my charts here, there are a total of 57 Shmitah years that were counted during the time of Bayit Rishon. Starting in 3409, there are exactly 59 Shmitah years to 3829, the year of Churban Bayit Sheini. What's the problem with this? Shmitah was still on "auto-pilot" for the first 7 years of Bayit Sheini, until after Ezra arrived (3416). The year Ezra arrived was a Shmitah year (3415).
There is another option in order to arrive at 59. If we take year 1 of the first cycle to be 3416, but only count 7 year cycles, then the 59th Shmitah is 3829.
We can figure out which of these 2 is at work by going backwards. It is said that the Great Yovel will be the 48th Yovel.
If we take everything to be according to Rebbi Yehudah since the time of Ezra, we see the following:
3929 + 1938 = 5768 (this is the Shmitah year, not according to our halachah l'maaseh)
49 * 48 + 3416 = 5768 (this would be the Yovel year)
So it seems that these calculations are based on the following:
- Counting of the Shmitah and Yovel starts the year after Ezra's arrival to Eretz Yisrael (i.e. 3416), as per the Rambam.
- The Yovel count is based on the count of Rebbi Yehudah, 49 year cycles, which is not in accordance to halachah for the time of the Beit HaMikdash, as recorded in the Rambam.
This is all made explicit later on the book, which after having glanced over, I see mentions the same calculation at least 1 more time.
The difference between this, and the 48th Yovel year that I mention elsewhere on this blog is that during the time of Bayit Sheini, there were 8 Yovel years, which pushes back the calculation by 7 years total, arriving at 5776.
Regarding the authorship of this book: This book is attributed to Rav Avraham ben David HaLevi, who is known as the 1st Ra'avad, as opposed to the more famous Ra'avad who commented on the Rambam, who was the 3rd Ra'avad.
(For more on Yovel, click here)