A magnificent life-size bronze horse in Italy has been dated at between 2300 and 2400 years old, putting it firmly in the classical Greek era, after scientists dated its clay core.
Marco Martini and Anna Galli, with the Department of Material Sciences at the University of Milan, said the dating of clay cores of bronze statues by thermoluminescence analysis is the only possibility of scientifically aging the casting of bronze statues because of the impossibility of directly dating a metal.
The pair, writing in the journal Applied Sciences, acknowledged it is a complex task. “Nonetheless, important results can be achieved by accurate analysis of the experimental data,” they said.
In their paper, the pair described their efforts in dating the clay cores from three important bronzes in Rome:
- The famous Lupa Capitolina, a bronze sculpture of a wolf suckling the mythical twin founders of Rome, Romulus and Remus. The has always been considered as the symbol of Rome itself;
- A life-sized bronze horse in the Musei Capitolini (Capitoline Museum) which, like the Lupa Capitolina, could be a Greek original or a Roman copy, such as many bronze statues in Rome; and
- The statue of Saint Peter in the Vatican, whose age has been long under discussion.
The researchers described a range of challenges in dating the works.
In the case of the Lupa Capitolina, the results were not accurate enough to precisely propose a date of casting, but the traditionally reported Etruscan origin of the work, perhaps the 11th or 12th century, is definitely ruled out, they said. The comparison with radiocarbon results shows good agreement for Medieval dating.
Classical Greek era
The horse that they dated was found with several bronze objects in 1894 in an old cellar in Rome, some of them of great artistic interest. The horse, heavily damaged, was transferred to the Musei Capitolini, restored, and has been on display since.
The researchers’ work dated the piece at 2300 to 2400 years ago, assigning the casting of the bronze horse to the classical Greek era, and excluding its casting from the Rome imperial period.
The statue of Saint Peter in the Vatican Basilica in Rome was dated at 680 years old, plus or minus 60 years, which puts its casting at the beginning of the 14th century.
This, they said, is in good agreement with the proposal of scholars who attribute the work to Arnolfo di Cambio.
They said the statue provided a particularly favourable clay sample, enabling the dating to be carried out with good precision.
Martini, M.; Galli, A. Thermoluminescence Analysis of the Clay Core of Bronze Statues: A Re-Appraisal of the Case Studies of Lupa Capitolina and Other Masterpieces in Rome. Appl. Sci. 2021, 11, 7820. https://doi.org/10.3390/app11177820