Shortly before sundown on the 29th of Adar, G-d commanded Moses regarding the mitzvah of sanctifying the crescent new moon and establishing a lunar calendar. This is the first mitzvah the Jews were given as a nation.
Moses had difficulty envisaging the moon's appearance at the exact moment of its monthly rebirth. After the sun set, G-d showed Moses the crescent new moon of the new month of Nissan, showing him the precise dimensions of the moon at the moment the new month is to be consecrated.
For the generations that followed, each new month was ushered in when two witnesses testified before the Sanhedrin (rabbinic supreme court) that they had seen the molad, the new moon. In the 4th century CE, Hillel II foresaw that the Jews would no longer be able to follow a Sanhedrin-based calendar. So Hillel and his rabbinical court established the perpetual calendar which is followed today -- until Moshiach will come and reestablish the Sanhedrin.
Links::
Lunar Time
Rosh Chodesh
The Molad
A few months after its creation, Napoleon's "Sanhedrin" (rabbinical supreme court) was dissolved. The Sanhedrin was created to approve certain religious regulations requested by the French "Assembly of Notables." The regulations were designed to blur the distinction between Jews and non-Jews.
The rulings of this pseudo-Sanhedrin were never adopted by Jewish communities.
Link:: Napoleon Bonoparte
Without miracles, we might come to believe that the laws of physics define reality. Once we witness the inexplicable, we see that it’s not a closed system, that there is a higher reality.
And then we look back at physics and say, “This too is a miracle.”
The miracle of a small flask of oil burning for eight days was this sort of miracle. The combustion of oil and oxygen generated light, and yet the quantity of oil did not diminish.
Then there are those small miracles that occur every day, those acts of synchronicity we call “coincidence,” because in them G‑d prefers to remain incognito, leaving all the laws of nature intact.
Indeed, that is an even greater miracle, that G‑d can achieve whatever He so desires non-invasively, as though He weren’t even there.
These were the sort of miracles the tiny band of Maccabees saw in their battles against the mighty Greek army. They fought bravely, but in their hearts they knew a great miracle happened here.
So too, when we open our eyes and hearts, we ponder those everyday coincidences and we awaken to the realization that there is truly no place void of this wondrous, unlimited G‑d.