Commentary for Avodah Zarah 19:4

If this document is post-dated, meaning the date of execution seems to be later than when the loan actually occurred, the power of the creditor to seize the debtor’s property is lessened. He will only be able to seize property that was in the possession of the debtor from the time written in the document.

The dating of documents begins with the Seleucid (Greek) rule over Babylonia (312 B.C.E). However, according to R. Nahman, there are some scribes who begin this count 6 years earlier, when the Seleucids began their rule over Elam, a land close to Babylonia. Thus this document may be precise, and should not be considered a “post-dated” document.

Aha b. Jacob says that perhaps he dated the document according to the date of the Exodus, which is 1000 years before the beginning of Greek rule. He just left off the thousands assuming this is clear (today we leave the “thousands” off of our Jewish dating). If so, this document indeed would be a post-dated document by six years.

Nahman, and then a baraita, both relate that in the Diaspora Jews count only according to the years of Greek rule.

This entire section is proof that today (meaning in Talmudic times) documents are dated from the years of the Greeks. There are two systems of reckoning the years in the Mishnah of Rosh Hashanah quoted here—one Jewish that begins in Nissan and one non-Jewish that begins in Tishrei. Today Jews all over the world count the year beginning in Tishrei. This implies that we are counting the year according to the rule of the Greeks and not the Exodus.
I should note that only in the Middle Ages did Jews began to count the years from the creation of the world. Such a system was not known in the Talmudic period.

“Genosia” refers to the ascension to the throne. The pagans, according to the baraita, celebrate both the old king’s ascension as well as that of his son.

Joseph interprets a verse in Obadiah in reference to the Romans. According to R. Joseph, they did not practice a hereditary monarchy. Nor do they have their own script or tongue.

The Talmud tries to interpret the “day of genosia” as reference to the king’s birthyday. But this fails too.

The Talmud now goes back to suggesting the “genosia” is a coronation day. The Romans do appoint sons as kings, but only upon request. Hereditary monarchy is possible but not automatic.

Antoninus here gets some advice from Rabbi as to how to achieve both of his aims while only asking the Senate for one of them. Below, the Talmud will explain why Rabbi cannot tell Antoninus what to do directly.

Here Rabbi gives him some advice as to how to get rid of his enemies.