Among the most illustrious grand masters of the order was Henry the Navigator. The Prince ensured the Order's position in history by devoting a significant portion of its funds to support his adventures in the 15th century. The establishment of the Iberian Union in 1581, when Philip II of Spain was acknowledged as Philip I of Portugal, took place at this same site. The aqueduct was constructed during the time that the Union lasted, which was from 1630 to 1640.