What other systems of reckoning years were used by the Jews?
A popular system used by Jews in the Middle East from antiquity even to the early modern era in some places is the "Minyan Shetarot," or "Era of Contracts." This system of reckoning coincides with the foundation of the Seleucid Empire in 312/311 BCE. As a rule of thumb, to reckon a date from Minyan Shetarot subtract 312 if the date falls before Rosh ha-Shanah, or 311 if it falls after the new year. Some medieval writers, such as Maimonides, calculate the civil date from the destruction of the Temple (traditionally from the 9th of Av falling in July/August in 70 C.E.).