The city of the sun and Parthenope: classical astronomy and the planning of Neapolis, Magna Graecia Nicola Scafetta * , Adriano Mazzarella Department of Earth Sciences, Environment and Georesources, University of Naples Federico II, Complesso Universitario di Monte S. Angelo, via Cupa Nuova Cintia, 21, 80126, Naples, Italy article info Article history: Received 22 December 2017 Received in revised form 12 May 2019 Accepted 19 May 2019 Keywords: Archaeoastronomy Magna Graecia Hippodamian city planning Greek religion Pythagorean doctrine abstract This paper investigates what may have been the cosmological and religious inspirations for the plan of the city of Parthenope-Neapolis (the historic centre of Naples, Italy), which was founded in the early fifth century BC by Greek colonists. Neapolis anticipated the strict orthogonal Hippodamian street grid plan. We argue that its geometry and geographical orientation was chosen so that Neapolis could be recognized as the city of Helios/Apollo (the sun-god of the Greeks) and Parthenope, the deified royal ancestor and/or the siren after whom the city was named. In fact, Neapolis's streets were cosmolog- ically oriented using a sixteen-rayed hexadecagram geometry to emphasize Apollonian/solar cults. The city was also planned using a Pythagorean decagram/pentagram design with golden section pro- portions and inscribed geometries to symbolize the Harmony of the Spheres. These geometries were apparently inspired by the specific paths of the sun seen from the city on the solstices. Moreover, a sort of celestial light show on the spring and autumn equinoxes connected the sun, the Somma-Vesuvius volcano complex, Sant’ Elmo hill, the constellations of Taurus, Virgo/Parthenos and Aquila with the cult of Sebethos and Parthenope, the parent gods of Neapolis. Finally, Vitruvius's ideal city design appears to indicate that the novel and advanced planning of Neapolis served as a prototype for subsequent Greek and Roman cities. © 2019 Elsevier Ltd. All rights reserved. Ancient cities were built in ways that related their urban form to the actions and interactions of a plurality of individuals, groups and institutions. 1 During the Hellenic period, starting from the fifth century BC, it became a customary practice among the Greeks to lay out new cities in a strict, orderly and orthogonal grid pattern in sharp contrast with the intricate and disordered geometries that had characterized older centres like Athens. 2 This innovative ar- chitecture was mostly developed by Hippodamus of Miletos (498e408 BC), perhaps a follower of the theories of Pythagoras (570e495 BC). In Aristotle's opinion, Hippodamus was the father of European urban planning. 3 The Hippodamian rectangular plan was particularly successful because it contributed to making urban organization more func- tional and related cities to their surrounding environments and landscapes by providing them with a well-defined orientation. Hippodamus's plan of Piraeus (451 BC) became a procedure to follow elsewhere. 4 His elegant design was widely accepted throughout the Greek world and was later adopted by the Romans. 5 The main parallel streets were termed plateiai in Greek or decumani in Latin, while the secondary streets perpendicular to them were termed stenopoi in Greek or cardines in Latin. 6 This urban structure also characterizes many modern cities. The decumani gave each city an orientation that was chosen according to some specific criteria, a typical one being the topog- raphy of the site. In Piraeus, for example, the decumani ran parallel to the coastline. Elsewhere the use of basic solar-astronomical points of reference e the cardinal points and the sun's position as * Corresponding author E-mail address: nicola.scafetta@unina.it (N. Scafetta). 1 A.T. Creekmore III and K.D. Fisher, Making Ancient Cities: Space and Place in Early Urban Societies, Cambridge, 2014. 2 The Hellenic Period covers the interval between the date of the first democracy in Athens (507 BC) and the death of Alexander the Great (323 BC). 3 L. Mazza, Plan and constitution e Aristotle's Hippodamus: toward an ‘ostensive’ definition of spatial planning, The Town Planning Review 80 (2009) 113e141. 4 D.W.J. Gill, Hippodamus and the Piraeus, Historia: Zeitschrift für Alte Geschichte 55 (2006) 1e15. 5 F. Haverfield, Ancient Town-Planning, Hamburg, 1913. 6 Throughout our analysis we will use the Latin terminology. Contents lists available at ScienceDirect Journal of Historical Geography journal homepage: www.elsevier.com/locate/jhg https://doi.org/10.1016/j.jhg.2019.05.004 0305-7488/© 2019 Elsevier Ltd. All rights reserved. Journal of Historical Geography xxx (xxxx) xxx Please cite this article as: N. Scafetta, A. Mazzarella, The city of the sun and Parthenope: classical astronomy and the planning of Neapolis, Magna Graecia, Journal of Historical Geography, https://doi.org/10.1016/j.jhg.2019.05.004