WATERLOO, Belgium — The region around this Belgian city is busily preparing to commemorate the 200th anniversary in 2015 of one of the major battles in European military history. But weaving a path through the preparations is proving almost as tricky as making one’s way across the battlefield was back then, when the Duke of Wellington, as commander of an international alliance of forces, crushed Napoleon.

A rambling though dilapidated farmstead called Hougoumont, which was crucial to the battle’s outcome, is being painstakingly restored as an educational center. Nearby, an underground visitor center is under construction, and roads and monuments throughout the rolling farmland where once the sides fought are being refurbished. More than 6,000 military buffs are expected to re-enact individual skirmishes.

While the battle ended two centuries ago, however, hard feelings have endured. Memories are long here, and not everyone here shares Britain’s enthusiasm for celebrating Napoleon’s defeat....