It was a town and county seat until the early 19th century.The castle in a dominant position over the Penentada hill, dominates the surrounding plain and the confluence of the Angueira stream with the Maçãs river. At the time of the Christian reconquest of the Iberian peninsula, the primitive line of limits between the Portucalense county and the kingdom of Leão developed along the left bank of the River Sabor until its confluence with the Angueira stream. This lane was guarded by four main sentinels: the Castelo de Milhão, the Castelo de Santulhão (both already missing), the Outeiro de Miranda Castle (in ruins) and this Algoso Castle. The castles of Penas Roias, Mogadouro and, although more distant, that of Bragança complemented this main defense of the northeastern sector.
