What were the names of the two people that promoted the use of the external staircase?
Around 1730, the Baroque style gradually began to break away from the defined Roman style of Baroque and gain an even stronger individuality, for two reasons: the rush to rebuild was subsiding, construction was becoming more leisurely and thoughtful; and a new clutch of home-grown Sicilian architects came to the forefront. This new generation had watched the rebuilding in the Baroque, and studied the ever more frequent engravings and architectural books and treatises arriving from the mainland. However, they were not like their predecessors (the former students of the Romans), and consequently were able to formulate strong individual styles of their own. They included Andrea Palma, Rosario Gagliardi and Tommaso Napoli. While taking account of the Baroque of Naples and Rome, they now adapted their designs for the local needs and traditions. Their use of resources and exploitation of the sites was often wildly inventive. Napoli and then Vaccarini had promoted the use of the external staircase, which was now taken to a new dimension: churches upon the summits of a hills would be reached by fantastical flights of steps evoking Vaccarini's mentor Francesco de Sanctis's Spanish Steps in Rome.Façades of churches often came to resemble wedding cakes rather than places of worship as the architects grew in confidence, competence, and stature. Church interiors, which until this date had been slightly pedestrian, came especially in Palermo to be decorated in a riot of inlaid marbles of a wide variety of colours. Anthony Blunt has described this decoration as "either fascinating or repulsive, but however the individual spectator may react to it, this style is a characteristic manifestation of Sicilian exuberance, and must be classed amongst the most important and original creations of Baroque art on the island". This is the key to Sicilian Baroque; it was ideally matched to the Sicilian personality, and this was the reason it evolved so dramatically on the island. Nowhere in Sicily is the development of the new Baroque style more evident than in Ragusa and Catania.
Vaccarini Napoli