For the first time, archaeologists have scientifically analysed ash residue from incense burners preserved at Pompeii, revealing the substances burnt as offerings to the gods in Roman households and the long-distance trade undertaken to acquire them.
In Roman households, incense was often burnt to offer smoke sacrifices to the gods, and many incense burners and censers have been found across the Roman world. However, the residues of the substances burnt in them rarely survive, making us reliant on ancient texts and images to teach us about Roman domestic worship.
The incredible preservation of Pompeii, buried in ash after the AD 79 eruption of Mount Vesuvius, provides a unique opportunity to advance our understanding.
“Ancient literary sources and visual representations show that the Romans burnt aromatic substances, such as frankincense, as well as various plants and herbs on their altars as offerings to the gods”, states lead author of the research, Dr Johannes Eber from the University of Zurich. “At several Pompeian altars, ashes and burnt residues have been preserved, though they have only rarely been subjected to detailed analysis.”
To tackle this, researchers analysed organic residues, ash pseudomorphs (biominerals formed in woody plants) and phytoliths (microscopic particles of silica formed inside plants) from two Pompeian censers to reveal what substances were burnt in them.
“The combination of advanced chemical and microscopic analytical methods makes the religious daily life of the people of Pompeii tangible,” explains co-author Philipp W. Stockhammer from LMU Munich, who initiated the scientific study.
The results were surprising: alongside local plants, the researchers found the first archaeological evidence for offerings of grape products (likely wine) and aromatic resins such as frankincense.
The offering of wine and frankincense together features in Roman writings, playing an important role in Early Imperial religious and funerary rites, but neither had ever been attested archaeologically.
Importantly, analysis of the resin indicates that it was not sourced from southern Arabia, where most frankincense used in the Roman Empire came from. Instead, it was likely obtained either from India or sub-Saharan Africa.
As such, this rare direct physical evidence for domestic cult practices at Pompeii highlights Pompeii’s integration into a trade network stretching far beyond the borders of the Roman Empire, indicating that the Romans went to great lengths to facilitate their everyday household worship.
“We’ve long known from ancient writers that the Romans burnt frankincense in their sacrifices”, concludes Dr Eber. “Now, archaeology confirms it: an incense burner with preserved ashes and traces of fragrant resins from a domestic shrine near Pompeii provides tangible proof – and a striking reminder of just how globalised the ancient world truly was.”