When two shlichim are used for a get. Plus metaphorical treatment of Persia, Rome, and Babylonia, and comparison of them insofar as who was good for the Jews. Also, a new mishnah and the requirement that a date must be included on documents, at writing and signing, which means the timing matters on a Jewish calendar in terms of the date switch at sundown. Also, Abaye and R. Yosef on issues of dates of the bills of divorce - even of the get isn't good, for some of these issues, a future child is not a mamzer. And the application of "lechathilah" and "bedieved" makes a real difference. Plus, the case of a husband who cuts the date out of the divorce - but we're not worried about this kind of trickery.