Documenting the early history of the grotto in the National Palace of Sintra (Portugal)

The National Palace of Sintra, the summer residence of the kings and queens of Portugal, underwent important transformations during the reign of Manuel I of Portugal (1495–1521). These changes significantly affected the water infrastructure of the building. Among numerous tanks and fountains, a very early 16th-century grotto was constructed. Its existence has gone unnoticed as it was completely refurbished during the 18th century. Nevertheless, it was described by a contemporary Spanish traveller. In this essay, we would like to present the original documentary and morphological details of the so-called Gruta dos Banhos and vindicate its role in the history of grottoes.