Could this pottery shard be a 1,000-year-old hand grenade? Signs point to yes

Archaeologists have analyzed the remnants of four medieval ceramic shards and found that one may have been used as a hand grenade. The gunpowder used was imported from China.

The Greeks invented the Greek fire a century earlier than the Byzantines did. They placed the material in jars to make bombs instead of using Greek fire. By the 10th century, the technology had spread to China, with Chinese soldiers packing gunpowder into ceramic or metal containers.

India may have had grenade-like weapons. A terra-cotta elephant filled with explosives was unleashed on an invading army. A mid 14th century Chinese book describes a flying-cloud thunderclap cannon made of cast iron shells that were roughly the size of a bowl and filled with gunpowder. Similar grenades first appeared in Europe in 1467 and have been a staple of warfare ever since.

In the 11th and 12th century Jerusalem, grenades were a fixture of weaponry. Small ceramic vessels, ranging from a few centimeters to 20 centimeters in diameter, are frequently found in excavation sites throughout the Middle East. Many vessels have conical bases and spheroid bodies, and this makes sense since they were used for many different purposes.

A plumb bob, a loom weight, a liquid sprinkler, a fire starter, a lamp, a smoking pipe, or parts of an apparatus for distillation are possible uses. They would have been used as containers to hold wine, honey, beer, medicines, scented oils, holy water, mercury, or perfumes. There is evidence that vessels were used as grenades. Residue analysis can help confirm uses, but very few have been conducted.

The site of the Crusader royal palace was also the site of the four ceramic vessel shards that the team decided to analyze. The Royal Ontario Museum houses all of the shards. One of the shards was orange with a reddish-brown interior, while the other two were gray-green and greenish, and the third was dense and gray.

None of the shards had been treated other than a light brushing and rinsing with water. The artifacts were excavated in the 1960s, so soil samples couldn't be taken. They used existing data on the composition of soils from that region of Jerusalem, mostly limestone and dolomite, with patches of chalk that break down into terra rosa and pale rendzina.

The researchers were most interested in shard #737. Sulfur and mercury, as well as magnesium, nitrates, phosphorus, calcium, lead, and iron, were found in the residual. It is believed that plant oils, glycerol, and animal fats are consistent with the vessel being used to hold oils, perfumes, or medicines and as a fuel source for a weapon or a lamp.

The authors think the possibility that it was used as a grenade is worth serious consideration. The thick walls would have been able to resist the rising pressure before detonation, the vessel was gray and undecorated, and the optimal size for a handheld grenade was described in historical accounts.

During the time of the Crusades, the vessels were used as grenades and held black powder. It has been suggested that black powder may have been introduced to the Middle East earlier, as early as these vessels from the 9th-11th century.

The other three shards had a small amount of sulfur and a small amount of fatty acids, which may have come from the surrounding soil. The authors concluded that the vessel was used as a container for oils. Animal fats, plant oils, salts, and mercury were included in Shard #742. The sulfur, mercury, and organic substances show the vessel may have held medicines.

Plant oils, animal fats, and sulfur were found in the residual from shard #744. It was also used to hold medicines, despite the high amount of sulfur.

There is a DOI for the journal PLoS ONE. There is a journal called "journal.pone.0267350".