some assume béarnaise refers to the béarn region, a former province now in the "département" of pyrénées-atlantiques, in southwestern franceto refer to the region of béarn however, the sauce has no tradition in the cooking of the area, and larousse has the name honouring henri iv of france, a native of béarn, and for whom the restaurant where the sauce was first shown was named. henri iv was often known as le grand béarnais