Dennis,

It's documented in VFP help under SET DATE Command.

>Hi--
>
>If you issue SET DATE SHORT, VFP no longer handles any dates before
>{^1601-01-01}. It throws an DATE/DATETIME EVALUATED TO AN INVALID VALUE any time you attempt to use a date prev to 1601 in any way.
>
>Are any of you Microsoft guys aware of the problem so it can get fixed?
>
>Thanks,
>
>Dennis