What are the minimum and maximum valid dates in Salesforce?
What is the valid date range in Apex, SOQL or SOAP API?
It is hard to find anything in the documentation
Initially I have found an answer here, but the link provided in that answer, was broken.
Finally found a corresponding valid link in the documentation
Minimum and Maximum Dates
Only dates within a certain range are valid. The earliest valid date is 1700-01-01T00:00:00Z GMT, or just after midnight on January 1, 1700. The latest valid date is 4000-12-31T00:00:00Z GMT, or just after midnight on December 31, 4000. These values are offset by your time zone. For example, in the Pacific time zone, the earliest valid date is 1699-12-31T16:00:00, or 4:00 PM on December 31, 1699.