How far forward and back can the IPhone calendar go?

I was looking through my calendar at old dates and I wanted to see how far back it could go. I got to 1895 and then I got tired.
(1) how far back can it go?
(2) how far forward can it go?

And please no estimations or guessing.

I remember i tried to see how far forward it could go and got to 2500s. It took about 15 minuites

Got to 10000 got bored