The 6 historical organs of the Basilica of Mafra were a truly innovative organ project. What makes of them a unique ensemble is not their number – a remarkable feature in itself – but the fact that they were built at the same time and originally conceived to play together. The present six instruments were built by the two most important Portuguese organ builders of the time – António Xavier Machado e Cerveira and Joaquim António Peres Fontanes – and were completed between 1806 and 1807.