In the 8th and 9th centuries CE, the center of Jewish life moved from Babylonia to Europe, so calculations from the Seleucid era "became meaningless". From the 11th century, "anno mundi" dating became dominant throughout most of the world's Jewish communities, replacing the Seleucid dating system. The new system reached its definitive form in 1178 when Maimonides completed the "Mishneh Torah". In the section "Sanctification of the Moon" (11.16), he wrote of his choice of Epoch, from which calculations of all dates should be made, as "the third day of Nisan in this present year ... which is the year 4938 of the creation of the world" (March 22, 1178). He included all the rules for the calculated calendar epoch and their scriptural basis, including the modern epochal year in his work, and establishing the final formal usage of the "anno mundi" era.