In the beginning, the spirit of Elokim hovered in the darkness over the deep. There was no light and no life. God was alone.
Then He made light; and then a great tent, separating the waters and exposing dry land. He brought forth grasses and trees, hung luminaries in the sky, called out fish and birds and animals and human beings. By the end of day seven, Elokim, who a week before hovered in that lifeless darkness, now beheld a tremendous world-tent; a palace of light and color and movement and life. What was He seeking?
Originally, our Jewish calendar did not have a fixed number of days in each month. Each month had 29 or 30 days, depending on when witnesses spotted the new moon and reported this to the Sanhedrin (High Court). Around three hundred years after the destruction of the second Templeand the accompanying exile, Hillel II (4th century CE, Eretz Yisra’el) instituted a fixed calendar which we use until this day. The year has an average of 354 days, with the months alternating in length: Nisan has 30 days, Iyyar 29, Sivan 30, and so on. (Heshvan and Kislev sometimes have 30 and sometimes 29. These are set in such a way to prevent certain festival difficulties. For instance, according to our calendar system, Yom Kippur will never fall on Friday. We ensure these by altering the length of Heshvan and/or Kislev). 
