Tishrei 1, Rosh Hoshanna is the Head of the New Civil Year. It is also known as The Feast of Trumpets. It begins October 2, 2016 at dusk. It is a High Holy day set-apart to blow shofars to call upon the LORD for His provision. Kings are called upon and coronated at the Civil year.
Nissan 1 is set apart for the Jewish calendar to recognize the Ecclesiastical (religious) New Year. This calendar was set by ADONAI through Moses when the Israelites came forth out of Egypt. Nissan is the Passover month where death passed over all who blood on their door posts…even the stranger was saved from their first born death and could leave Egypt with the Hebrews.
Thus, the Hebrew calendar has two Month One: Tishrei and Nissan and the Hebrew calendar also has two Month Seven: Tishrei and Nissan.
They are seven months apart and both are to be remembered. This shows us a calendar that is circular and does not have a Greek beginning and end. And, events don’t have to be on the exact hour and day…as in Greek thinking…but it is a time-period of themes that float in similar fashion showing patterns set show God to men.