Most historians agree that the original Sauce Hollandaise recipe originated in Normandy (a region famous for its butter and use of butter in cooking) and was first known as Sauce Isigny, after the town of Isigny in Normandy. The recipe can be found in recipe books dating from the 1800s.
There are also claims that the recipe exists in recipe books from the 17th and 18th century, but closer examination of the ingredients and preparation calls this into question. For example, there is a recipe for "sauce a la hollandoise" in the 1758 edition of Marin's Dons de Comus. However, as this recipe includes flour, bouillon and herbs and does not include egg yolks, it can be argued that it is not the same recipe at all, merely sharing the same name. Likewise the recipe by Francois Pierre de La Varenne in Le Cuisinier Francois appears similar to Sauce Hollandaise but cannot be said to be the same.
At some point the recipe was renamed to Sauce Hollandaise (meaning either from Holland or Holland-style), although historians have different explanations for the recipe being renamed. One explanation is that during World War 1 little butter was produced in France and so it had to be imported from Holland, with the result that the recipe was renamed to reflect the source of the butter. Another is that Holland is well known for the quality of its butter, so the name is based on this. Unfortunately, despite general agreement that this is a French recipe, there does not seem to be a definitive answer for the reference to Holland.
There are a number of variations on the Sauce Hollandaise recipe, differing mainly in the ratio of ingredients (how much butter to how much egg yolks, etc.). There are also a number of recipes similar to Sauce Hollandaise but including additional ingredients (e.g. spices).