On the turn after you destroyed the tomb, did you get a message like this:

Strategos, the body of Megas Alexandros has been prepared for the long journey back to Pella. Now it is time for you to return him to be buried beside his ancestors. Last time, the Ptolemies attacked and stole him away, but this time, you will personally escort him home.
Then your general would go and end his turn in Pella, and get another message and a title.