jan 1, 1341 - children disappear from Greyhawk

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Numerous children disappear from the City of Greyhawk.
The children simply disappeared at night, never to be seen again, though sometimes they were replaced by simulacrums that committed vile blasphemies and had to be destroyed.

A base date of 576 CY, when the Catalogue was completed, was modified by 'fifteen years ago' to arrive at the date of 561. Which leads to a question that the answer still eludes me. If the Glossography was compiled in 998 CY then should the references therein be based upon that date?

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