Alexandria built to celebrate birthday of Alexander the Great
Alexander the Great founded Alexandria in 331 BC and an examination of the topography of the city today allows the identification of the essential elements of the original urban system as it was laid out. It is suggested that the site was chosen for religious and symbolic reasons just as much as for commercial and topographic requirements.
Alexandria becomes the prototype for a series of Hellenistic towns designed as ‘king’s towns’ that aimed to make explicit the divine power of their founder, Alexander of Macedon.
A grid aligned on the Sun and Regulus
The researchers Giulio Magli and Luisa Ferro with the Politecnico of Milan claim in a paper published in the Oxford Journal of Archaeology that the orientation of the orthogonal grid, which was based on a main longitudinal axis of the city (Canopic road), show that this axis is orientated to the rising sun on the day of Alexander the Great’s birth, July 20th, 356 BC by the Julian calendar. At the time of foundation, ‘King’s Star’ Regulus was also rising along that same alignment, and this bright star was known later as ‘Qalb al-Asad‘, which is Arabic for ‘the heart of the lion’, a perhaps obvious connection with the Lion of Macedon.
According to a comment on the science website Physorg, the sun’s declination changes only about a fifth of a degree each day around July 20th, so there would be about 4-5 days when the sunrise is at declination +20.5°, +/- 0.5° and aligned with the road. The alignment repeats, with the sunrise inching northward day by day, around May 22nd.
The researchers looked at other examples such as the town of Selucia on the Tigris and the funeral monument of Antiochos I at Nemrut Dag in Anatolia to investigate whether this was just coincidence. With Alexandria and Selucia at the same latitude, the sun with a flat horizon would set in alignment with the longitudinal axis at Selucia the very same days as rising in Alexandria. Due to the slight difference in latitude the sun was actually setting along this direction on the days around July 27th, with a slight displacement, but in any case still very close to the date of birth of Alexander. At Nemrut Dag, the plinths holding the colossal statues in the eastern terrace point to sunrise on July 23rd (and May 22nd) – in addition the terrace also points to the rising of Regulus, which also occurred around the 23rd July at the Nemrut Dag latitude during the reign of Antiochos I.
Source: Oxford Journal of Archaeology
- Luisa Ferro and Giulio Magli THE ASTRONOMICAL ORIENTATION OF THE URBAN PLAN OF ALEXANDRIA, Oxford Journal of Archaeology, DOI: 10.1111/j.1468-0092.2012.00394.x ( PDF)