Not an exact answer
From another forum...
Filemaker represents dates internally as the number of days since 1/1/0001.
Hence, you can just set a field (of type date) equal to 5968, and then use the Month, Day, and Year functions on that field, to return the month, day, and year offsets relative to 1/1/1. Note that this will include leap years. This would give 5/4/17.
If you want to make the returned date relative to some other date, say, January 1, 2010 (733773 days after 1-1-0001), you would instead set date to 733773 + 5968.
There is also a function on Brian Dunning's site that will take a julian date number and convert it to a gregorian or julian date which may be of interest. http://www.briandunning.com/cf/239 -- note commas in function should be changed to decimals.
FileMaker Timestamps are I believe stored internally as a number; it is currently: 63424632584
It is the number of seconds since: 1/1/0001 12:00 AM
35065.25 * 86400 // convert to seconds
Timestamp ( Date (12;30;1899); Time (0;0;0))
Result (as FileMaker Timestamp): 1/1/1996 6:00 AM
This seems a little weird to me, as the Delphi TS, from FileMaker's point of view, should be negative, but FileMaker shows it as a positive number, if the result is number.