During the Second Temple period, Jews in Palestine and in the Babylonian exile were notified of the new moon's arrival by fire beacons that were lit across the mountaintops. It is to be presumed that when the ancient Israelites were still nomadic shepherd tribes in the wilderness, they reckoned time entirely by the moon, as did all nomadic peoples. After settling in Palestine where they began to observe the agricultural seasons, they also began to reckon according to the position of the sun, and with time, developed a system which equalized the sun-year and the moon-year. The month, the year, and the festivals were figured entirely by observation, by testimony offered that the moon had appeared and had been seen. Although astronomic calculation were gradually instituted in connection with the calendar, the Jews were not certain of its exactness and continued to resort to witnesses. The authority to hear this testimony and through it to establish the beginning of the month, the intercalation of the calendar, and the dates of the festivals was vested in the Sanhedrin (Jewish high court in Palestine during Roman and Byzantine periods). The Sanhedrin gathered on the thirtieth of the month, formally proclaiming the New Month only after it had heard evidence of witnesses who had actually seen the new moon. If the new moon was not sighted on the thirtieth day of the month, the proclamation would be made on the thirty-first. Once the witness' testimony was accepted, the head of the court proclaimed the new moon with the words, "It is hallowed." Then all the people assembled would respond, "It is hallowed! It is hallowed." The witness was given a lavish meal, and fire beacons were lit on the mountaintops to notify Jews wherever they lived, including the Babylonian diaspora, of the new moon's arrival. This ceremonial procedure is described in Mishnah Rosh Hashanah.. Click to view enlarged How did they light the beacons? They used to bring long poles of cedar and reeds and olivewood and flax fluff which they tied to the poles with a string. And someone used to go up to the top of a mountain, and set fire to them, and wave them to and fro and up and down, until you saw the next one doing the same thing on the top of the second mountain. And so on on top of the third mountain. Click to view enlarged Whence did they carry the chain of beacons? From the Mount of Olives [in Jerusalem] to Sartaba, and from Sartaba to Grofina and from Grofina to Hauran, and from Hauran to Beit Baltin. The one on Beit Baltin did not budge from there, but when on waving to and fro and up and down, until he saw the entire Diaspora before him like one bonfire [because the inhabitants, upon seeing the beacon fire on the mountaintop, used to light torches]. (There is no general agreement as to the exact locations of these places. Scholar Obermeyer locates them as follows: Sartaba is Karn Sartaba, five kilometers from the western bank of the Jordan; Grofina Arafun, a hill situated among the Gilead range of mountains; Hauran south of Damascus, and Beit Baltin is Beiram which is some miles northwest of Pumbeditah, in Babylonia.) When the rabbis determined that the lighting of fire beacons was dangerous, the system was stopped and messengers were sent out. Because it took time for the messengers of the Palestinian Sanhedrin to reach the distant Babylonian communities, it was decreed that outside of Palestine, in the lands of the Diaspora, festivals were to be observed for two days instead of one. This added second day was called "the second holiday of the Diaspora."[*] Around the middle of the fourth century CE, the astronomical calculation of the calendar was established with such precision, that the the elaborate system of hearing witnesses was discarded. Proclaiming and spreading the word of the new moon came to an end. [*] An exception was made in the case of Yom Kippur which, because of the hardship of fasting, could not be prolonged. Rosh Hashanah was also an exception in that it was observed for two days even in Palestine, for Rosh Hashanah was also the New Moon, the first day of Tishrei. Even in Palestine it could not always be ascertained on the preceding day whether the particular day was the first day of Tishrei or the last day of Elul. Even after the calendar was established, the observance of the "second holiday of the Diaspora," was retained outside of Israel. [back] Hayyim Schauss' essay, "The Jewish Calendar" in The Jewish Festivals: A Guide to their History and Observance.(Schocken 1996, reprinted with the permission of the Union of American Hebrew Congregations) Illustration: Title page of tractate Rosh Hashanah with illustration of priests lighting a fire to signal the new moon. Hebrew Latin manuscript, Amsterdam, 1700-1704.