What were the special circumstances which made it obligatory on the part of Dantes to go to Elba

Danglars complains to M. Morrel that Dantès delayed the ship's progress at the Island of Elba for a day and a half. Dantès clears his responsibility for this delay by clarifying to M. Morrel that he merely stopped at Elba to deliver a package for the deceased Captain. The package was for the Emperor Napoleon himself.