The cloth that came from the sea
is neither a tale nor a miracle. It is simply a truth. At least, it is a truth simple enough when one considers nature and expects it to provide endless wonders.
Afore the blank pages of history
our ancestors must have had such expectations. We might say that to them nature was the fulcrum of religious feelings and the levee point of both sensibility and intelligence. On the Mediterranean shores, the prime settlers faced the sea and, at the call of its endlessness, they generated timeless cultures.

These could only develop through cultural interactions, however distant.

One actor in this interplay is known as Sea Silk or Bisso : Surely the inhabitants of ancient Sardinia, as the Cretans and Phoenicians met with weavers-dyers from either continental Chaldea or the Nil valley, then began the millennium old saga of the fabulous Sea Silk.

Firmly planted on soft sea-floor, a giant bivalve mollusc -Pinna nobilis- produces tufts of fibbers which, thanks to punctilious care - carding, cleaning and spinning - can be weaved into an exceptional cloth : it is not only silky with a golden glow, it is also elastic, solid (when stretched, the threads can be a mere 2/100th millimetre and retain all of their strength), weather and fireproof. Of old, vast quantities of sea-shell were fished, so as to produce enough thread to weave or embroider dresses for persons of high rank the least of them being courtesan ladies and dancers : when wearing a Sea Silk cloth, one appears as dressed with glowing light. So, there once was a very profitable industry of Sea Silk, twinned with that of Sea Purple, both making use of the never-ending manpower provided by the numerous population of slaves.

The giant mollusc lives in shallow waters
where it was fished intensively. To this purpose the gatherers used a specific tool, mentioned by Plino as pernilegum, which consisted of two curved iron rods that worked like pliers at the end of a wooden handle of adapted length. All the fishermen had to do was to get hold of the shell between the two hands of the pernilegum and then rotate it at a 90° angle to uproot the shell from the sea floor. The pernilegum was used by the fishermen of Tarento (Italy) and, elsewhere, other tools served the same purpose. Thus, a rope with a split-knot could be used, only it required two workers : a diver who tied the loop to the shell and a sailor who pulled the catch on board.
But, whatever fishing tool was used, the full length - some 25 centimetres - of the tuft was cut off from its base, which is within the shell itself. To this purpose the shell was opened and hence died.

The gathered tufts,
each one weighing about 1,5 gram, must be repeatedly washed in soft water during 12 days, until the fibbers become salt free and attain their optimal elasticity. Alternatively, the tufts are set to dry in a place secluded from daylight and fairly ventilated.
To lighten the colour of the fibbers and, hence, enhance their luminescent quality, the tufts were dipped in cow urine. But, since citrus fruits became common in the Mediterranean world, lemon juice is used instead of urine, to the same end in a 36 hours bath.
Afterwards, there comes more washing, done with soapwort herbs, and alternate periods of drying in the shade.
When this is over, the tufts still show impurities and incrustations. To clean these away, the tufts are carded, first with a plank sparred with nails, the with a fine metallic brush.
After carding - the silky golden locks having lost 5/6 of their initial weight - comes spinning. The clean fibbers are now so tenuous that they seem intangible, and the lightest and most sensitive touch is required. Thus, spinning was solely trusted to young maiden whose hands had not yet been roughed with harsh labour.
The required spindle is about 30 centimetres long and weighted with lead, such as the ones used in Tarento (Italy) or Cyprus. The end product is either a single thread, good for embroidery work, or doubled and twisted hence stronger as required for weaving.
The sea-silk was weaved on looms either vertical - such as the Greek or Persian ones - or horizontal - as used in Mesopotamia.
All in all, the gathering of a thousand giant shells was required to produce as little as 250 grams of sea-silk thread.

Sea-silk was only dyed with sea-purple.
The fact that both cloth and dye are by-products of the marine world can hardly be considered a coincidence. The sea-purple dye (indigo dibromid) is produced by specialised glands of the murex, an other mollusc with a twisted, fluted, spiked, hard shell.
To produce more dye, the murex-shells were picked at mating times, that is during the full moons of March and June, when the molluscs gather in huge numbers.
Thus, every springtime, shell pickers could be seen walking the Mediterranean shoal waters which their specially woven little round basket. Near many antic cities off the shores of North Africa, Southern Europe and the Middle East, huge deposits of shells, often mistaken for natural hills, are indeed testimonials of the importance and ubiquity of the sea-purple industry.
The foul smelling crimson producing glands are located next to the intestine of the mollusc and they must be taken whole. Hence, the hard shell must be broken with one measured knock, without squashing the animal. The glands were laid with sea-salt in huge earthen jars, where they were left to macerate for 3 days. Then the mixture was diluted with half its volume of soft water, before being put to slow fire for 10 days. To assure continuous temperature control, the lead caldron containing the stuff was placed in a pit laid with bricks, linked by an horizontal pipe to a distant fire-place. As the boiling went on, the mixture was filtered until it became perfectly liquid. The dye gave hues ranging from light blue to bright pink, from dark crimson to blackish purple.

The fall of the flourishing production
of sea-silk came during reign of Emperor Justinian (500 AC) when two Persian monks brought to the Constantinople's court silk-worm eggs and mulberry trees which they had "obtained" on the Chinese border.
Production of the new silk-cloth initiated in the island of Chio and, in no time it spread to Sicilia before reaching all Mediterranean shores. The giant sea-shell could hardly compete against the silk-worm whose production is definitely more abundant. As the luxury cloth market lost all interest for the sea-silk, its industry disappeared to survived only as a household activity whose techniques will be handed as secrets from mother to daughters. Up to now, woven or embroided, rare and priceless pieces of sea-silk celebrate exceptional events or honour important visitors.
In Southern Italy, the city of Tarento had been famous for its sea-silk industry : antic writers called tarentinides the extra-light dresses that were too close-fitting to meet the standards of modesty. All the same, the looms of Tarento went silent and then, the precious thread was solely used for embroidery.

What is left today
comes principally from the sea-silk workshop of Tarento. It all amounts to less than one hundred pieces, that might be found in various museums, most of them Italian. Unfortunately, many of these remaining pieces are kept in safety and, hence, not displayed. There is :

LIONS & PALM-TREE Following 09-11 attack in New-York : 2 lions protect the palm tree, which represents peace. Unbleached linen, threaded and woven by hand, embroided with sea-silk itself dyed in a light hue of sea-shell purple. Chiara Vigo - 2001

• at the Museum für Naturkunde in Berlin : a pair of woven sea-silk gloves offered by the bishop of Tarento to king Frederic William II when the latter visited Napoli in 1822 ;
  
  
• at the Field Museum of Natural History in Chicago : a muff bought in Tarento for the Chicago World Exhibition in 1893. It was made "fur like" by sewing whole tufts of sea-silk in layers on canvas, resulting effectively in a likeness of fur, but with the famous golden shine of sea-silk ;
  
  
• of greater antiquity, other remnants might be seen in few European churches or at exhibitions following various archeological finds. The origins of such pieces cannot always be precisely asserted but they certainly come from Middle Mediterranean regions and probably from Southern Italia, Sicilia, Sardinia. Among such rare items :

  • a knitted cap of pure sea-silk, dated from 14th century. It was found in Saint-Denis (France) where it is kept, at the Musée d'Art et d'Histoire ;
  • a chasuble said of Saint-Yves, kept in the homonymous basilica (12th century) in Louannec (Brittany-France). The origin of this religious dress is given as Arabo-Spanish from Sicilia. But, as it shows the Tree of Life between two gryphons facing each other which is a traditional pattern of Sardinian iconography, the cloth might as well have been woven in Sardinia. In such case, French Benedictine monks who did rebuilt many Sardinian churches during the 12th century could have brought the cloth back home.

  

  
  

Above, the identity card of Pinna nobilis...
Endemic to the Mediterranean Sea, this bivalve mollusc is noted for its size : over three feet in length.
It lives, planted upright on sand-banks at a depth of 3 to 30 meters, were posidoniae weeds prosper.
The two halves of the shell are of greyish-brown colour and their rough surface hosts algae, diatomae and other small sedentary sea-creatures. The Pinna nobilis shows little signs of activity but it filters every hour no less than 6 litters of water, just to feed on plankton. For such purpose, the two half shells are left slightly ajar.
Both shells are triangular and pointed at the base. A somewhat straighter line denounces the male. They are thin, fragile and yet made of three layers : the outer one is hard and corneous, the intermediary is made of calcareous prisms, the inner one is mother-of-pearl ranging from bright yellow or red in the lower part to whitish-glassy in the upper part.
For its reproduction Pinna nobilis depends on a spongy alga, Padina pavonia, which inhabit the giant shell and, in return, collects and breeds its gametes until they are left to the flows of the sea at the most favourable moment, sometimes in May. The larva period lasts from 5 to 10 days. Obviously, the more abundant the population of Pinna nobilis is in the shoal waters, the highest the probabilities for fecundation ; on the contrary, if the population dwindles its futur might be endangered.

Optimal conditions for maintenance of sufficient density of the Pinna-beds are :

• luminosity ;
• on polluted water with a slow but steady flow to ensure enough food transit ;
• vitality of the environing prairies of posidoniae weed, actually threatened by various human activities and pollution.

Unlike other members of the Mytilaceae family, who attach themselves to rocks, Pinna nobilis burrows its pointed end into the sand-banks where, if conditions allow, it prospers in great numbers. 

Its anchor is given by a tuft of filaments, in the manner of roots, which are the result of processing and curing in water of a burr secreted by a gland - called the byssus gland - located near the base of the tongue-foot body of his movement.