The Sky of Salamanca (El Cielo de Salamanca) (Foto: GSL)
In the cloister of the Patio de Escuelas Menores of Salamanca, there is a mural known as El Cielo de Salamanca (The Sky of Salamanca) depicting some Ptolemaic constellations, the Sun and Mercury. It is part of a painting (c. 1483–86) that was hidden for a century and a half. Rediscovered in 1901, it was moved to its current location in 1953. Those who visited it shortly after its completion describe it as a magnificent astrological vault. However, in 1960, Zinner stated that the mural was a representation of the celestial vault of an August day in 1475. This legend has been taken as a fact ever since. We have shown in JHA, the most relevant journal about the History of Astronomy, that it is a speculative proposal with many inconsistencies. The real story is much more interesting. Understanding it leads us to explore manuscripts from the 15th century to understand the relevant role that astrology played at that time. We often make the mistake of seeing the past with the eyes of the present.
During the second half of the 15th century in the vault of the Library of the University of Salamanca, where the chapel of San Jerónimo is today, a splendid mural was painted. Deterioration and adaptation works destroyed two thirds of the painting, the rest remained hidden from the public for two centuries. The preserved part was restored in the early 1950s and moved to its current location in the Patio de Escuelas Menores. In the current painting it can distinguish [See in detail HERE]: The Sun, next to Leo, and Mercury, next to Virgo, the five signs of the Zodiac –Leo, Virgo, Libra, Scorpio and Sagittarius–, the constellations of the northern hemisphere –Bootes, Hercules and Serpentarium–, and the constellations of the southern hemisphere –the Southern Crown, the Ara, the Centaur and the Hydra, to which Corvus and Crater.
The professor at the University of Salamanca Rafael Laínez Alcalá, who studied it before the transfer, gave it the name by which it is now known: El Cielo de Salamanca (The Sky of Salamanca). Great name although it later created confusion because some thought it referred to the sky seen from Salamanca, naturally this is not the case as it includes constellations from the Southern Hemisphere, such as Centaurus, not visible from Salamanca. Laínez Alcalá said that it was an astrological sky and speculated with the idea that it represented the zodiac on the date of birth of Prince Juan (06-30-1478) but he ruled it out because on that date the Sun was in the sign of Cancer while In the painting the Sun is in Leo and the Sun enters Leo on July 13 or 14.
In 1960, German astronomer Ernst Zinner said that the painting represents the sky on August 6, 1475, erroneously associating it with the opening date of the Library. The historian Gisela Noehles-Doerk in 1992 asked her friend the astronomer H. W. Duerbeck to determine for the period 1474 – 1494 a date where the Sun is in the sign of Leo, Mercury in Virgo and where neither the Moon, Venus, Mars, Jupiter and Saturn are in Leo, Virgo, Libra, Scorpio or Sagittarius, as they appear in El Cielo de Salamanca. He responded that this circumstance occurred between August 14 and 29, 1475. The problem is that, as will be seen, H. W. Duerbeck interpreted the zodiac sign as synonymous with the zodiac constellation. However, those who have followed him do not seem to have noticed this error because since then his interpretation, with minor discrepancies, has generally been assumed to be true. To justify the date, multiple reasons have been speculated (an exceptional event , a very rare sky, the date of the Assumption, etc.). The bizarre history of the astrological vault “El Cielo de Salamanca (JHA 55 (1) 2024 shows that the Sky of Salamanca (El Cielo de Salamanca) does not correspond to the position of the planets on a specific date.
