The Children of Israel began building the "Mishkan" (also called the "Tabernacle"--a portable sanctuary to house the Divine presence in their midst as they journeyed through the desert) on the 11th of Tishrei of the year 2449 from creation (1312 BCE) -- six months after their Exodus from Egypt, four months after the revelation at Sinai, and 80 days after their worship of the Golden Calf. The construction of the Mishkan, which followed a detailed set of instructions issued to Moses on Mount Sinai, lasted 74 days, and was completed on the 25th of Kislev; but the Divine command to erect the edifice came only three months later, on the 23rd of Adar, when Moses was instructed to begin a 7-day "training period."