Year Zero

It's funny how everyone has their own idea of when year zero was. You probably know about Unix epoch time. That's a year zero in my book. I found two more year zeroes today: one was hand crafted in some code I inspected and started 1st Jan 1996. The other was the SQL Server 2000 datetime column type. That turns out to be 1st January 1753 (when the Gregorian calendar that we use now was adopted). I'm not sure how you're supposed to represent dates before 1753 in SQL Server 2000 other than as strings, and anyone who knows any better, I'd be glad to hear from.