Wikipedia
According to Galician, Asturian and Portuguese mythology, the Mouros are a race of supernatural beings which inhabited the lands of Galicia, Asturias and Portugal since the beginning of time. For unknown reasons they were forced to take refuge under the earth, and now they are usually seen by people in the surroundings of castros and long barrows. The Mouros work with gold, silver and gem stones with which they make up enormous treasures that are protected by cuélebres.
The Mouros do not usually go out of their dwellings, except for taking food, and also in special dates like Midsummer.
Galician anthropologists had formed the theory that the Mouros are the opposite character of traditional galician peasant.
The Mouros encantados some times appear as giants or warriors, and they include the legend of the moura encantada and the legend of the mourinhos or maruxinhos, a very small elf like people who live under the ground.