The castle was built between 1279 and 1282 by order of Charles I of Anjou, from whom it gets its original name, the Maschio Angioino (the Angevin Keep). The project was entrusted to the French architect Pierre d'Agincourt. It was called the "new" castle after extensive renovations commissioned by Alfonso of Aragon, following his victory over the French. Its original appearance is today visible only in the Chapel of Santa Barbara, with frescoes (almost entirely vanished) by Giotto and his student, Maso di Banco. The reconstruction, entrusted to Catalan and Tuscan artists, was directed by the Majorcan Guillermo Sagrera, who extended and fortified the structure. The marble entrance arch of the castle is of considerable interest: numerous artists participated in creating this celebratory declaration of the Aragonese victory, among them Francesco Laurana and Domenico Gagini. Within the castle are housed the Neapolitan Society of National History (founded in 1875), possessing roughly 170 thousand volumes, drawings, prints, and manuscripts; and also the Civic Museum, which guards a rich collection of art works originally in Neapolitan churches.

Construction of the palace began in 1600 by order of viceroy Fernando Ruiz de Castro, count of Lemos. Work on it, directed by the architect Domenico Fontana, stretched out to the middle of the seventeenth century. Every other arch of the facade was filled in, for structural reasons, by Luigi Vanvitelli. In the nineteenth century, Umberto of Savoy had eight statues of the kings of Naples placed in the niches. (The statue of Charles V is the work of Vincenzo Gemito.) A further significant initiative was undertaken by Gaetano Gasse between 1838 and 1858. The Appartamento Storico (the Historical Apartment) on the piano nobile, richly decorated and furnished, can be visited for its vast collection of art objects, including paintings, sculpture, clocks, furniture, tapestries, and frescoes. The former Appartamento delle Feste (Holiday Apartment) has, since 1925, housed the Vittorio Emanuele III National Library, which boasts an extraordinary collection of a million and a half volumes, among which are palimpsests from the third century, codices from the fifth century, and miniatures and incunabula from the fifteenth and sixteenth centuries. The famous Herculaneum papyri are also kept here for study.

The construction of the Archbishop's palazzo was ordered in 1289 by the then Archbishop of Naples, Enrico Minutolo. The original entrance where is now the 'carriage gateway' of the seminary used to be in Via Sedil Capuano. On the site where the palazzo was built, there was an ancient basilica of the pre-Christian period (Sancti Laurentis ad Fontes), of which remains of the atrium were found during some recent restoration work. The present building is the result of the re-structuring carried out in the 17th-century, first by Cardinal Decio Carafa in 1613, and later by Cardinal Ascanio Filomarino: the latter entrusted the work to the Carthusian monk Bonaventura Presti, who carried it out between 1643 and 1650, enlarging the building in length and opening the three portals, in grey piperno stone, on the facade. The frescoes by Giovanni Lanfranco in the Cardinal's quarters, representing landscapes, are of the same period. In these rooms, which have recently been restored, there is an interesting art collection, which will form the main part of the future museum to be opened in the Church of Santa Maria Donnaregina Nuova.

From Public Square of the Plebiscite, passing for Public Square "Trieste and Trento", it is caught up "S. Carlo Avenue" where we can admire to our right homonymous Theatre of S. Carlo. Constructed in 1737 for wanting of the King Carlo III of Borbone, the plan was entrusted to the architect Giovanni Antonio Medrano. November of 1737 was inaugurated 4, the patron saint's day of the monarch. February the 12 of 1816 a furious fire destroyed it completely. Ferdinando IV di Borbone check then the reconstruction to the architect Antonio Niccolini, already taken part for the reconstruction of the facade; the second inauguration had January the 16 of 1817. Today represents one of the maximum theatres of the world; a lot important is the shows of grand operas that every year come inserted in the billboard of the show.

Built in the fifteenth century, the palazzo was the residence of an eminent representative of the Aragonese court, Diomede Carafa, Count of Maddaloni. Its facade is constructed of rectangular rusticated blocks, and contains a marble gateway (1466) framing the original wooden door. Decayed though they are by time, twelve panels are still visible in which the coat of arms of the Carafa family is engraved. The architecture is Catalan in style, but the decorations have a classical or late Gothic flavour. Two busts of emperors remain, as well as a statue over the gate, and two heads depicting the owner and his wife (at the corners of the facade). Inside, in the courtyard, there is a marble copy of a bronze horse's head that was a gift to Carafa from Lorenzo the Magnificent. (The original was transferred to the National Archaeological Museum in 1809.) After a period of misfortune, the palazzo was returned to its former splendour in the eighteenth century by Francesco Carafa di Colubrano. It had another period of splendour in the last century after being acquired in 1813 by the lawyer Santangelo, who established there an extraordinary art collection that has since been dispersed. Unfortunately, the palazzo has fallen into a state of neglect and decay.

This palazzo was built on the right-hand side of Piazza San Domenico in the XVI century. The original facade with its basement in the local grey "piperno" stone, two sets of pilaster strips and sculpted frieze, were damaged in the 1688 earthquake. The entrance and part of the basement remain. Duke Agostino Saluzzo di Corigliano carried out extensive internal and external restoration work when he acquired the palace in 1727. This included the Duke's second floor official residence, with some features in rococo style. The "Galleria Grande" has paintings from the second half of 17th century on the walls and ceiling. The entirely mirrored study, the "Cabinet", was created by Filippo Buonocore in 1732 which includes decorative work attributed to Bartolomeo Granucci. The palazzo now houses several departments of the "Orientale" University.

The palazzo was built in 1513 by Giovanni Donadio (called "il Mormando": "the Whisperer") as a residence for Bartolomeo di Capua, Prince of Riccia and Count of Altavilla. It shows off the estimable forms of Renaissance Neapolitan architecture, enlivened on its facade by the alternation of white marble and gray piperno, and by windows with varying dimensions. On the cornices of the second order the motto "MEMINI" ("I Remember") is inscribed. In the eighteenth century, architectural projects partially destroyed the building's original symmetry which had been based on the alternation of filled and empty spaces. During this period a portal with simpler forms replaced the original, and, most importantly, openings were cut along the base of the walls to house new shops. Inside, the great hall contains the remnants of a fresco (almost entirely destroyed during the bombardments of 1942) by Francesco de Mura depicting Charles of Bourbon saved by Bartolomeo di Capua in 1744 during the Battle of Velletri. An inscription under the vault records that in 1701 this palazzo was the center of the Macchia conspiracy. The palazzo currently houses the Campania Bureau of Archives.

A few steps from the seaside it opens the wonderful square of the " Plebiscito “, that offers the visitor a beautiful sensation, cither for the wideness or for the architectural beauties; in particular it has to be observed that putting ourself in definite points of the square a wonderful landscape; can be admired cither of Naples’ gulf with the Vesuvio in the background, or of the imposing mass the of " San Martino's chartreuse " and of the near Sant' Elmo's castle.  The actual configuration of the square has been achieved two through fundamental stages, the construction, at to the beginning of the 16th century, of the Royal Palace and the building in 1817 of the " Basilica of San Francesco from Paola “, of its ample hemicycles and of the two lateral palaces.

Called "Morocini Field," from the name of an old fortification, this area was already urbanized even before the expansion of the city walls during the Angevin period. It was during that period that it assumed the role, which it still has, of a market. It would not be until the second half of the eighteenth century, with the work of Francesco Securo, that it obtained its present organization (unfortunately, speculators have erected an ugly building on its side toward the bay). The exedra had the purpose of tying the rectangular outline of the piazza, defined by the masses of the shops, to the facade of the church of Santa Croce. Two fountains with obelisks were arranged on the long side. The church, also the work of Securo (1786), closes off its northern side. Behind the west side is the block that houses Saint Eligio, which had been closely tied to the church of San Giovanni a Mare before the demolitions of urban renewal. Saint Eligio was built in 1270, near the place where Conradin of Swabia was beheaded. Opposite is the church of the Carmine, which used to comprise (in a linkage between convent, fortification, and wall that has since disappeared) the city's eastern seaward edge.

Situated at the end of Via Tribunali, the castle takes its name from the nearby Capuan Gate (Porta Capuana). The castle was built as a fortress in the second half of the 12th century by the Norman King William I, known as William the Bad. The castle has been frequently altered and enlarged, first by Federico II of Swabia and later by the Angevin kings, although the later only occasionally used the castle, preferring Castel Nuovo as their domain. After the departure of the Angevins Castel Capuano passed to the Aragonese. Alterations over the centuries ended with its adoption for use as the Palace of Justice and prison, on the orders of the viceroy Don Pedro of Toledo in the 16th century. In 1858- 1861 it was radically restored by Reigler, keeping, however, its function as home of the Tribunal which it retains to this day. The Chapel of the Sommaria, a square building dating from the 16th century and decorated by the Spaniard Pedro Rubiales, is of particular interest.