Qual é a data mais antiga (ano) que pode ser adicionada
The first day you can select in Outlook’s calendar is April 1, 1601
The last day you can select in Outlook’s calendar is August 31, 4500
Why are these dates chosen? I don’t know. I do know that the entire system of Windows uses the date 01/01/1601 as a base for file dates and Active Directory uses it for logon dates, so perhaps the Outlook team had some fun with that (although putting Easter eggs in applications is no longer allowed at Microsoft)? And perhaps August 31, 4500 is Microsoft’s end-of-the-world prediction?
Fonte Trivia do calendário