Alexander the Great's Diary was located by Rick, Evelyn, and their son Alexander O'Connell, in an abandoned Hindu temple along the Indus River in India. Unfortunately while Jonathan Carnahan was trying to pry a gem from a statue's forehead, he unknowingly set off a booby-trap which resulted in the diary being destroyed.
History
The diary was owned by Alexander the Great, he wrote in it detailing his daily life during his conquests in Northern Egypt. In his entries he referenced to having the Scrolls of Thebes with him, which he checked out from the Library of Alexandria.