By Val Doughty - Volunteer Guide

The Night Sky and telling the future

In ancient times the night sky was hugely important in people’s lives and with just the naked eye and in most places, relatively little light and air pollution, phenomena such as the Milky Way would have appeared far more vividly than it does today.

The night sky could be used as a calendar for some of our ancestors, for example Sirius, the brightest star in the Northern hemisphere, rises above the horizon in August and for Egyptians this usually heralded the start of the flooding season of the Nile and indicated it was time to move off the flood plains. Timekeeping, navigation and agriculture were entwined and understanding how to read the night sky was a part of those systems.

Astronomy, a natural science that studies celestial objects and phenomena, Astrology studies the motions and relative positions of the planets, sun and moon interpreted in terms of human characteristics and activities. For the majority of human history Astronomy and Astrology were seen as a similar discipline, that the belief that events on earth and in the sky were entwined. However, by the 17th century, and the start of the period which has come to be known by some as ‘the Age of Reason’, the two subjects became separated from one another with Astrology demoted from being an equal partner to become regarded by many as a more of a pseudoscience.

Hadrian, fortune telling and the stars

The appreciation of constellations dates back many thousands of years and by Hadrian’s time most of those in the Northern Hemisphere, the ones that we are most familiar with today, had been identified, including those of the 12 zodiac signs. However, what is less well known is that an episode in Hadrian’s life was to have an impact on future development of star charts.

During this period, astrology was more widely accepted as a legitimate means of foretelling the future; Hadrian’s great uncle, Aelius Hadrianus, was regarded as a master of astrology, and he is reported to have prophesised that the newborn Hadrian would come to rule the world. The horoscope of Hadrian’s father predicts the birth of an illustrious son who would punish many. Hadrian was born 24th January 76 and in his own horoscope, which has been published several times, the positions of the sun, moon and planets show he was set to become ruler of his world, and it foretold not only his wisdom and education, but also his childlessness and death from illness. Hadrian took prophesies and omens seriously, but whether or not doing so made such things self-fore-filling or not is a matter which remains hotly debated to this day.

When Hadrian travelled through the eastern province of Bithynium (Modern Turkey) in AD123, it is thought this is when he first encountered a young 12-year-old boy called Antinous.  Young Antinous was from Bithynium and born in 111. From ancient accounts, we also know that he did not come from a wealthy family and may even have been a slave. Hadrian fell in love with him and took Antinous into his imperial court where the boy was educated and spent his time travelling with Hadrian for the next seven years.

In 130, Hadrian and Antinous travelled to Egypt, and it is here that tragedy struck and Antinous drowned in the River Nile.  Hadrian was heartbroken and founded a city called Antinoöpolis near the site of the drowning, declaring Antinous a god. Shortly after Antinous’ death, Hadrian’s Astrologers rather conveniently noticed a new star which had appeared suddenly in the constellation of Aquila, the Eagle.

“Hadrian declared that he had seen a star which he took to be that of , and gladly lent an ear to the fictitious tales woven by his associates to the effect that the star had really come into being from the spirit of Antinous and had then appeared for the first time”.  Cassius Dio (born circa AD 150, and another prominent native of the province of Bithynia)

Aquila the Eagle is in the band of the Milky Way, its southern star Altair, one of the brightest stars in the northern hemisphere, forms the southern point of the bright “Summer Triangle”. It lies almost overhead in the summer months for most of the northern hemisphere.

Perhaps the most influential astronomer of the ancient world was Ptolemy, born in AD100 in Alexandra, Roman controlled Egypt. In his “Almagest” of 150, he listed 48 constellations; and the constellation Antinous is listed as a sub-division of Aquila, containing 6 stars. It has been speculated that Ptolemy may have created the constellation himself, possibly at Hadrian’s request. The original Almagest is sadly lost but from copies of copies, many in Arabic and Greek, the first ‘modern’ printed edition was produced in 1515.  Antinous has become widely accepted as a separate constellation and depicted in publications by Mercator and Tycho Brahe amongst others, showing the boy Antinous being carried in the claws of the Eagle.  

However, sometime in the 19th century the constellation became obsolete, it must be after 1825 as it was depicted on a boxed set of 32 constellation cards entitled ‘Urania’s Mirror’ sold as an “attractive but educational item”. (National Maritime Museum, Greenwich)

Astronomic Orientation - Hadrian the architect and astrologer

‘Astronomic orientation’ is a term which is used to refer to a building which has been oriented towards an astronomic event, for example the spot where the sun is rising or setting during the days of the solstice or equinox.

There are three buildings in or around Rome which are associated with Hadrian and show both the sun and time architecturally: The Pantheon, the Villa Adriana near Tivoli and Hadrian’s Mausoleum.


The Pantheon, a temple dedicated to all the gods, was built in Rome in 27 BCE by Marcus Agrippa. The original building was rectangular and supported by a colonnade on all sides, a classical temple style with the entrance in the southern façade. Twice destroyed by fire, the Pantheon was redesigned and rebuilt under Hadrian. In remains one of the best preserved Roman architectural monuments you can visit in Rome today. Hadrian’s rebuild included a cylindrical core of concrete faced with brick, which supported the largest concrete dome ever built at that time, between AD118-119, culminating in an impressive 8-metre diameter oculus or ‘eye’ which is the single source of light for the entire building.  It is likely that the oculus was originally surrounded by a painted belt of the zodiac. Externally the dome was golden with glistening gold and bronze sculptures.  Reflecting the rays of the sun, it must have been an impressive sight and a stunning focal point for the city.

Hadrian inverted the previous orientation and the facade of the temple to face north, so no direct sunlight could enter from the door. Each day at noon, the sun came through the oculus, creating a spot of light which illuminated the north side of the building. Depending on the date, the spot of light appeared at different heights.  In winter, it falls on an area that is very close to the top of the dome and during the summer solstice, the sun creates a large circle of light directly onto the floor. When observing the monument, the sun passes through the oculus and into the building, at different times of the year, it is possible to (approximately) know the day of the year and the hour of the day by looking at the position of the sunbeam.

The second monument with an astronomic orientation is the personal residence of the emperor, the Villa Adriana near Tivoli. Built on a hillside well outside of the limits of Rome, construction on this UNESCO World Heritage Monument was started by Hadrian in around 117, about the same time as the Pantheon was being redeveloped. At first, Hadrian used it as a rural retreat, but he grew to prefer his villa in Tivoli to the palaces in Rome and started using this it as his official residence from around 128. The villa complex covers a vast area, with forty buildings and artificial terraces, set on different levels, of which around 30 remain. Many structures reflect influences from different cultures within Hadrian’s empire including Egypt, Greece, and Rome itself.

Recent work by the archaeologist Marina De Franceschini and the archaeoastronomer, Giuseppe Veneziano, have provided a re-evaluation of the Accademia Esplanade, which is the name given to the highest of the artificial terraces of the villa and its main buildings, the Accademia and Roccabruna (a belvedere commanding a wide panoramic view). De Franceschini and Veneziano  noted that  the esplanade was astronomically oriented along the solstitial axis, an imaginary line which connects the rising point at dawn of the Winter Solstice and the setting point at sunset of the Summer Solstice.


The third building I wish to discuss is the mausoleum of Hadrian in Rome (now Castel Sant’Angelo) which was completed in 139, a year after Hadrian’s death. A large part of the original structure is still preserved.  Ancient sources describe a chariot of the Sun, driven by the Emperor himself once adorned the top of the Mausoleum. The burial chamber had three oriented niches which remain intact (NE&W) and two large window tunnels to the east and west. At the Summer Solstice, in the morning, the sun’s rays enter the east window tunnel and cast a rectangle of light on the north and west niches and in the afternoon the sun’s rays enter the west window tunnel and cast a rectangle of light in the north and east niche.                                                                                        

Nearer to home, the principia, or headquarters building of the first stone fort at Vindolanda was geographically oriented to the south, rather than the north like its successor, meaning that the sun shone on a magnificent frieze devoted to a Sun God.  One of the few surviving fragments of this sculptured relief depicts the Sun God and this is now in the Great North Museum in Newcastle. 

This blog has been written as part of our Roman Holiday Project.


Architecture and Archeoastronomy in Hadrian’s Villa near Tivoli, Rome -

Marina De Franceschini & Giuseppe Veneziano

The Symbolic Use of Light in Hadrianic Architecture and the ‘Kiss of the Sun’ -

Marina De Franceschini & Giuseppe Veneziano


The Iconography of Sacred Space: A Suggested Reading of the Meaning of the Pantheon -

Christiane L, Joost-Gaugier

The Role of the Sun in the Pantheon’s Design and Meaning -  Robert Hannah and Giulio Magli

National Maritime Museum, Greenwich

Villa Adriana (  Ian Ridpath