How do we know that Albus was born in 1845?

I think it was given that Dumbledore was 150-years-old by book 5. So 1995-150 = 1845. Plus things coincide with Grindewald and whatnot. 24.49.35.99 03:29, April 22, 2010 (UTC)

Dumbledore was born in 1881. Ron jokingly said that Dumbledore was 150 in the 6th movie. --JKoch^{(Owl Me!)} 05:18, April 22, 2010 (UTC)