361 ON JESUS’ LAST SUPPER every year, but it is clearly true for the Creation week: on the 4th day of the first year the lesser luminary was a full moon. It seems that Al-Biruni was aware of a general introduction like that of 4Q 320 quoted above 30. As for the thesis of a hidden calendar, it should first be noted that the most common Hebrew word for “ month ” is çdj 31, whose natural meaning is “new”, that is, “new moon ”. Any other meaning is a distortion. Now, at the time of the exodus from Egypt, a new calendar was introduced (Exod 12,2): “ This month shall be for you the beginning of the months”. Rabbinic tradition understands that this reckoning from Nisan gives the dating of the festivals and the kings, while the Creation year begins at Tishri, six months later (m.Rosh ha-Shanah 1:1), all according to the lunar calendar with its Babylonian month names. But the night of the first Passover in Egypt and the departure of the Israelites occurred in full darkness (Exod 12,29-31), which is to say, at the time of a new moon. Elsewhere it is said that Passover has to be celebrated bybah çdj d[wml (Exod 23,15; Deut 16,1); this is usually translated “at the appointed time in the month of Abib”, but can be better understood as “at the appointed time at the new moon of Abib”, especially since both passages state that the feast is a memorial of the departure from Egypt. The moon signals the specific time (see Gen 1,14), but as in the case of the Creation week, the plain meaning refers only to the first year and no explanation is given for any adjustment in the following years. Something is hidden — or never existed. Later, in the Hellenistic and Roman periods, the Babylonian lunar calendar prevailed, but we do not know when and how the calendrical change was enforced 32. Anyhow, the purpose of both Jubilees and the Cairo document makes sense, although we do not know which secret See too J.T. MILIK, Ten Years of Discoveries in the Wilderness of Judaea 30 (London 1959) 152. The other one jry derives directly from “moon”, and indicates a period of 31 about 30 days, without any calendrical implications, see Exod 2,2; Deut 21,12; 2 Kgs 15,13. Some think this occurred in Palestine after the battle of Karkemish in 604 32 BC, after which Palestine came under the Babylonian supremacy, see E. AUERBACH, “Der Wechsel des Jahres-Anfang in Juda im Lichte der neugefundenen babylonischen Chronik”, VT 9 (1959) 113-121; A. LEMAIRE, “ Le sabbat à l’époque royale israélite”, RB 80 (1973) 161-185. But no hint of the change can be found in Jer and 2 Kgs. Later Ezra still uses the numbered