Archbishop Usher calculated the age of Earth based on the Book of Genesis, using the lifetimes of the patriarchs, reigns of kings, etc.
He determined that our planet was created 4,004 years before the Birth of Christ, on the 26th of October, at 9 o'clock in the morning.
A google search will provide reams of info
© Charles N. Pope, US Library of Congress. All rights reserved.