The most important Portuguese baroque monument was built by the King D. João V. The first stone was laid at an uncommonly flamboyant ceremony celebrated by the Patriarch of Lisbon, on November 17th, 1717. Financed by the abundance of Brasilian gold and driven by the monarch's ambition to rival the splendour of Papal Rome, the works grew out of all proportion. After several alterations the King ordered the living quarters to be increased to accomodate 300 friars. At this time the works employed 50.000 workers in addition to the 7.000 soldiers who were involved in auxiliary work. Although the Basilica was consecrated in 1730 the building was far from finished and works were to continue for a number of years after the death of the King, in 1750.

The Basilica has two carillons from Antwerp with a total of 92 bells and more than 200 tones weight, considered the best and biggest in the world; and a unique grouping of six organs with their own repertoire designed and built between 1792 and 1807.