I have read that Louis XVI and Marie Antoinette were both buried in unmarked graves after their executions during the French Revolution. On January 18, 1815, during the Bourbon Restoration, their bodies were exhumed and moved to their current location in the necropolis of French kings at the Basilica of St. Denis.
My question is, if they were buried in unmarked graves, how could their bodies be positively identified (or were they even positively identified)?