Construction of the Church of St Nicholas began in the early 18th century, as part of the general reconstruction in Sicily following the devastating earthquake of 1693.

The long interval between the beginning of the building, to designs by Rosario Gagliardi, and its completion in 1776 under the supervision of Bernardo Labisi, probably accounts for various peculiarities and inconsistencies of design, and the introduction of Neo-Classical elements.

Moreover, the principal doorways are revivals of 15th-century architecture, based on the style of Vignola or Domenico Fontana. The large central window of the west front, with its "ears" and curvilinear tympanum borrows from the repertoire of Andrea Pozzo and resembles work elsewhere in Noto by Francesco Paolo Labisi (for example, the Chiesa del Carmine).

The facade, the composition of which is comparable to those of the church of Notre-Dame, Versailles, and the pre-revolutionary church of Saint-Roch in Paris, was started in late 1767 (the nearby campanile bears the date 1768) to designs of about 1740 by Gagliardi.

In the 19th century the dome had to be reconstructed twice, ending up as a Neo-Classical construction, after collapses caused by earthquakes.

In the 1950s much refurbishment was carried out, not entirely successfully, for example the trompe-l'oeil of the vertical elements and the tempera decoration of the vaults by the painters Arduino and Baldinelli, as well as major alterations to the high altar and the organ.

Most serious however was the replacement of the original pitched roof of the nave by a heavy loft of Roman brick and concrete which was probably one of the causes of the collapse of 1996.

https://en.wikipedia.org/wiki/Noto_Cathedral