Why was the Edict of Nantes important in the history of France?

The Edict of Nantes (French: édit de Nantes), signed in April 1598 by King Henry IV of France, granted the Calvinist Protestants of France (also known as Huguenots) substantial rights in the nation, which was still considered essentially Catholic at the time. In the edict, Henry aimed primarily to promote civil unity.