Edict of Roussillon

The Edict of Roussillon () was a 1564 edict decreeing that the year would begin on January 1 in France.
During a trip to various parts of his kingdom, the King of France, Charles IX, found that depending on the diocese, the year began either at Christmas (at Lyon, for instance) or on 25 March (as at Vienne), on 1 March, or at Easter.
In order to standardise the date for the new year in the entire kingdom, he added an article to an edict given at Paris in January 1563 which he promulgated at Roussillon on 9 August 1564. It started being applied on January 1, 1567.
The 42 articles that comprised this edict concerned justice, except the last four, added during the king's stay at Roussillon.
It was article 39 that announced a January 1 start date for every year henceforth.