When Filipe II of Spain became King Philipe I of Portugal he also became the Master of the Order of Christ. Using this new title he ordered Filipe Terzi to construct an aqueduct to give the convent and the lands of the Seven Hills abundant amounts of water.
A grand work of hydraulic engineering was therefore built within the conventual landscape. It is 6 kilometres long with a total of 180 arches needed to carry water above the ground. A particularly audacious part of this construction is within the Pegões valley region - 58 full back arches at the deepest end of the valley are set on top of 16 broken arches erected over grand masonry starlings, known as pegões.
This construction was completed in 1619, finishing with a row of great arches attached to the Southern façade of the convent and the fountain found in the Main Cloister (a work accredited to Pedro Fernandes Torres).