6,000 Men and a Sunken Ship: The Talmud's Curious Chronicle of the Roman Method of Coral Harvesting (Rosh Hashanah 23a)
Intro
The Queen Farida of Egypt red coral parure by Ascione, made in 1938 in Naples, Coral Jewellery Museum. By ascione - http://www.ascione.it/, GFDL, https://commons.wikimedia.org/w/index.php?curid=5880885
The Talmud discusses the harvesting of precious coral, referencing a verse from the Book of Isaiah about a "tzi adir" which Rav interprets as a large ship used for collecting coral.1
This is an unusual instance of the Talmud documenting a contemporary general technological practice at relative length, similar to Pliny’s earlier Natural History.
The coral collection process is detailed: a ship, weighed down with sand, sinks to the sea floor, where divers (בר אמוראי) attach coral to flax ropes (אטוני דכיתנא). The sand is then removed, causing the ship to rise and pull up the coral.
This method employs either 6,000 men for a year, or 12,000 for six months, emphasizing the labor-intensive nature of coral harvesting.
The Talmud then explains that coral is highly valued, traded for twice its weight in silver.
The Talmud then goes on to say that the Romans and Persians control three significant ports (פרוותא). The Romans focus on coral (harvesting them with the methods mentioned in the previous section), while the Persians specialize in harvesting pearls,2 with Persian ports designated as royal ports.3
Comparison with known history and science
The method described in the Talmud for collecting coral is intriguing, but it does not align closely with known historical coral harvesting techniques, especially considering the specifics such as using sand to sink a ship deliberately.
While the Talmudic passage reflects a correct understanding of the high economic value of coral and the general use of labor and tools like ropes in its collection, the specific method described (using a sand-loaded ship to sink and rise) is not supported by historical evidence.
Point-by-point breakdown:
1. Large Scale Labor: While coral harvesting could indeed involve a significant number of people due to the value and demand for coral, the numbers mentioned (6,000 to 12,000 men) are hyperbole.4 Traditional coral collection was labor-intensive but typically involved far smaller, more manageable teams.
2. Sinking Ships with Sand: The technique of loading a ship with sand to sink it intentionally and then removing the sand to allow it to rise is not documented in historical accounts of coral harvesting.
From a physics perspective, it wouldn't work, since once it sank, it would no longer be buoyant, unless it was fully enclosed and airtight, like a modern submarine.
Ancient and medieval coral collection was generally done either by diving to pry coral loose from reefs or by dragging nets and tools across the reef to break off pieces, which could be done from smaller boats without the need to sink them.
3. Use of Flax Ropes: The use of ropes to collect coral could be historically accurate, as ropes and nets were common tools in maritime activities. However, the specific method of tying ropes to coral and using a sinking-and-rising ship to uproot it is not attested in historical records.
4. Economic Value: The claim about coral's high value is accurate. Coral has been prized for centuries, especially red coral from the Mediterranean, used in jewelry and decorations, often fetching high prices.
The Passage
״וצי אדיר לא יעברנו״ —
אמר רב: זו בורני גדולה.
היכי עבדי?
מייתו שית אלפי גברי,
בתריסר ירחי שתא,
ואמרי לה: תריסר אלפי גברי,
בשיתא ירחי שתא,
וטעני לה חלא,
עד דשכנא.
ונחית בר אמוראי,
וקטר אטוני דכיתנא בכסיתא,
וקטר להו בספינתא.
ונטלי חלא,
ושדו לבראי,
וכמה דמדליא — עקרא ומתיא.
ומחליף על חד תרין בכספא.
תלת פרוותא הויין:
תרתי בי רומאי,
וחדא דבי פרסאי.
דבי רומאי -- מסקן כסיתא,
דבי פרסאי -- מסקן מרגנייתא,
ומקרייא: פרוותא דמשמהיג.
[...]
Apropos coral, the Gemara cites a relevant verse: “Neither shall a tzi adir be able to cross it” (Isaiah 33:21), i.e., it will not be able to traverse the river that will issue forth from the Temple in the future. What is this tzi adir?
Rav said: This is a great ship [burnei] used to collect coral from the sea.
The Gemara explains: How do they perform this collection of coral?
They bring six thousand men to work for twelve months of the year,
and some say they bring twelve thousand men for six months of the year.
And they load the ship with sand
until it sinks to the bottom of the sea.
A diver descends
and ties flax ropes around the coral
and ties the other ends of the ropes to the boat.
And then they take the sand
and cast it overboard, and the boat rises once again to the surface.
And as it rises, it uproots and brings the coral with it.
The Gemara comments: And this coral is so precious that it is exchanged for twice its weight in silver.
The Gemara further notes: There are three ports in those places.
Two belong to the Romans,
and one belongs to the Persians.
In the one belonging to the Romans, they raise up coral,
whereas in the one belonging to the Persians, they raise up pearls.
And the Persian ports are called royal ports.
[...]
For other stories of diving in the Talmud, and its danger, see my recent series.
מרגנייתא - from Greek margarítēs, compare also the cognate Hebrew מרגלית.
פרוותא דמשמהיג - see my previous piece, for another place in the Talmud where this same term is used.
On Talmudic hyperbole, see my previous piece.