Copying a page
From OPOSSEM
Unlike moving a page, there is no built-in facility to copy a page, i.e., create two copies of the same page, with duplicate copies of the edit history prior to the copy time.
Similarly, while one can merge two edit histories into one, one cannot copy the edit history from one page to another while still retaining the original page separately.
An extension is provided with a "copy page" facility, namely Extension:Duplicator.