The IAHS 2018World Congress will be held in Naples, a unique city in the world.

While it is our practice to associate the memory of the origin of the city to the name of the mermaid Parthenope,who was the godmother of the city located at Monte Echia hill, nevertheless Neapolis, the new city, is the founder core around which has developed (over the centuries) the entire city of Naples.

The Antique Centre of Naples corresponds exactly to that of Neapolis which was founded around 470 BC, by the Cumans in the east of Parthenope, whichwill be called Palepolis. Neapolis was born either because Parthenope had been destroyed by the Etruscans or because it was not allowed urban expansion.

Neapolis, stretchedover a wide terrace overlooking the sea that rose to the north and west and thensloping down towards the sea, is organized according to the urban plan ofIppodamo da Mileto with three decumani/streets, arranged in the east-west axis,and with a series of cardini/roads, orthogonal thereto.

Neapolis, with it sthirty thousand inhabitants dedicated to maritime and commercial activities, in 328 BC had the possibility of having protection by the Romans. In 327 BC, the popular class of Sanità origin, in opposition to the aristocratic class of Greek origin, dismissed the security offered and Rome sent an army to be siege the city. Only the intervention of the Principes Civitatis, favourable to the treaty with Rome, allowed the Romans to get in Neapolis, in 326 BC, receiving the triumph. At Neapolis, even in Roman times, the Greek names of institutions and judges remained

With the Imperial age, Neapolis expanded outside the old city walls affecting south, the current area of the UmbertoI St.; south-west the current area of G. Bovio Square, G. Sanfelice St. and dePretis St.; west the current area of Gesù and Santa Chiara Squares.

The Greek-Roman Neapolis, lost its pre-eminencein the maritime-commercial field due to the emergence of Puteoli (the current Pozzuoli, Naples), acquires the character of positive climatic weather and a place of culture and art facilities. The Neapolis, with its charming, elegant, festive and peaceful characteristics among suburbs of Miseno, Baia, Pausilypon, Herculaneum, Pompeii, was the Epicureanism teaching centre, and represented, indeed,the real Athens of the Western world.

The prosperity of the city is guaranteed by the activities of architects, marble workers, wood workers, steel workers and craft activities of the goldsmiths.The Decumanus Major, along which opened the Forum, the theatres, the Temple of Castor and Pollux, was the centre of commercial, social and religious activities of those Greek-Roman citizens of Neapolis, which were, however, becoming more and more Neapolis citizens.

Around the 553 A.C., Neapolis became another time a Greek city, passing under Byzantine rule. It begins the era of the Byzantine Duchy that will last until the eighth century. The language returns to that of Homer and the precisely political system reminds the one of a Greek city. During the four centuries of the Duchy, the city is troubled by constant struggles for aims of conquest of the Longobards and the incursions of the Saracens.The city retained the Greek-Roman structure and only modest expansions occured towards the sea, as in the area Morocino

With the advent of the Angioini, a French dynasty, Naples was renewed to become the beautiful capital of the kingdom encompassing the entire southern Italy, with the sole exception of Sicily. The city expanded with Charles I d'Angiò according to the directives already undertaken by the Normans-Svevi. Its walls on thesouth-eastern border were enlarged to include in the urban perimeter of the Morocino and all the coastal zone  to Santa Maria la Nova; Castel Capuano and Castel dell'Ovo  were expanded and renovated; it was  built in the Campus Oppidi area, in just four years, New Castle, Palace and fortress symbol of the Angioina monarchy.

With the first Angioini kings, deeply religious, there was a great development with the religious buildings and the city is enhanced by some architectural gems such as the new Cathedral, the Church of St. Lorenzo, the Church of Donnaregina, the Church of St. Mary of Carmine and the monumental Santa Chiara. In addition to religious buildings they were built important sewerage works, paved the streets with paving stones and baked bricks, encouraged the inclusion in the city of foreign colonies that gave great impetus to business, maritime and banking activities; it were issued edicts that anticipate building regulations.

Vittorio Gleijeses writes on the Naples of the Angoini: “…during the reign of Robert d'Angiò, Naples had a cultural and economic boom period; it was one of the most cultured city in Europe and attracted artists, writers, poets, as well as merchants and bankers. In this capacity andnot as a writer, so will pass to posterity that Giovanni Boccaccio lived for a time in our city.”

In the fifteenth century the city, closed in the Aragonese city walls, was affected by a consistent building densification growing in height on itself. The Aragonese was a Spanish dynasty.

Hippodamian urban structure, made up of decumani and cardini, has remained unchanged now a days even though the building products have been, inevitably, more or less changed in the approximately two thousand five hundred years of life of Neapolis.

Vittorio Spinazzola in "Nobiltà di Napoli" writes: “Those who look at or think back all that portion of our city that ranks among the Incurabili to the north and S. Marcellino a mezzogiorno, the streets of west Mezzocannone and those of St. Nicola to the east, cannot but remain surprised by this very regular square crossed from east to west from those three parallel arteries,which, to be clear, are the ways of Forcella, Tribunali, Sapienza from north to south by all those parallel and symmetrical streets that intersect, chasing inall its length. Is a miracle of preserved available through twenty-fivecenturies, and yet we see, as it were, at the ceremony at which the first Greeksettlers traced, according to their custom, the sacred lines that had to close and split their little Naples; since they had not finding other encumbrances on the ground that those they were able to draw a so minute and fine zoning plan.”