Hospital de Santo António was designed by the English architect John Carr and the first stone laid on 15 July 1770. It was to replace the old D. Lopo de Almeida Hospital, located on Rua das Flores.
The original design contemplated a neo-Palladian building with four huge wings and also included a Greek-cross-plan church with a pinnacle, set in the centre of the large cloister. The hospital was never completed in full, indeed, it underwent major alterations. In the end, the west façade and the church were not built, while the length of the north and south wings is about fifty per cent less than the original 178 metres envisaged by John Carr.
It is one of the most extraordinary examples of neo-Palladian architecture constructed outside England. It is also the first neoclassical building in the city, which greatly influenced the architecture of Porto.
It was classified as a National Monument in 1910.