In the classic marble sculpture, the Trojan priest Laocoon is assailed by a fearsome sea serpent. While clearly in pain, over time the interpretation of Laocoon's countenance has been constantly re-evaluated from different historical perspectives.

Alfred Hitchcock's film Torn Curtain contains a very long, silent passage in which an East German agent is beaten nearly to death, and then asphyxiated by having his head stuffed into an oven. Accused of pandering to sadistic tastes, Hitchcock was keen to defend the authenticity of the scene: how could two people in a kill-or-be-killed situation exchange wisecracking insults in the traditional Hollywood manner when each was saving his breath to try to kill his opponent?

A similar critical question had arisen two centuries earlier, in connection with the classic depiction of pain in Western sculpture, namely the marble group, probably from the 1st century AD, of Laocoon and his sons being attacked by a monstrous sea serpent. The sculpture was excavated in Rome in 1506 and was acquired for the Vatican collections, where it still is today.

In the centre of the group is the Trojan priest Laocoon (pronounced 'lah-ock-o'-own'), entangled by the snakes which had been sent to punish him for his hostility to the will of the god Apollo: in the war between the mainland Greeks and the Trojans, Laocoon had warned the Trojans not to accept into the city of Troy the gift from the Greeks of a wooden horse, which the Greeks had filled with fighting men ready to destroy the city.

Virgil: 'bellowing'
In his epic poem the Aeneid, the Roman poet Virgil had described Laocoon's reaction to the sea serpents sent by Apollo to kill him and his sons. As Laocoon tried to fend them off:

"at the same time he raised to the stars hair-raising shouts like the roars of a bull when it flees wounded from a sacrificial altar and shakes the ineffectual axe from its neck":

Clamores simul horrendos ad sidera tollit:
quales mugitus, fugit cum saucius aram
taurus, et incertam excussit cervice securim.

Winckelmann: 'Nobility'
In the eighteenth century, Laocoon and the sculpture were studied in detail by the historian Johann Joachim Winckelmann (1717-1768) and the philosopher Gotthold Ephraim Lessing (1729-1781). Both scholars agreed that the sculptor did not show Laocoon bellowing in the manner described by Virgil, but each invoked a different reason for his view.

Winckelmann, writing in 1755 as a critic and historian of art, identified the essence of ancient Greek sculpture - the sculptors of the Laocoon were Greeks - as 'noble simplicity and quiet grandeur' ('eine edle Einfalt und eine stille Grösse') which, in the case of the Laocoon sculpture, would incite us to noble thoughts and actions by showing, pace Virgil, Laocoon's heroic, dignified and silent struggle to resist the serpent.

Lessing: 'groaning'
Lessing, in his essay Laokoon (1766), treated the sculpture from the point of view of a philosopher of aesthetics. He was concerned to use the sculpture as a case study in defining the difference between visual arts and literature: literature was absorbed in time, and through conventional signs (e.g. letters and words) which in themselves meant nothing. In the visual arts, on the other hand, the dimension of time hardly existed, and the means of representation were similar to the things which they represented.

Thus literature could describe horrible things without using horrible words, while the representational arts could only represent the horrible by showing us the horrible. As that would produce not a noble work of art but one which would put us in much the same distress as Laocoon, producers of visual representations tend to tone down the unpleasant features, and that is why, according to Lessing, Laocoon is not roaring like bull: his jaw is tightly constricted in a position that would enable him to utter only a low groan. Lessing's difference of opinion from Winckelmann arises from the former's different background as an aesthetic philosopher.

Bell: 'Silence'
That however does not exhaust the diversity of backgrounds from which a view of the Laocoon group can be proposed. Another worthwhile critic of the sculpture was the anatomist Sir Charles Bell (1774-1842). Bell's career include the care of the wounded from the battle of Waterloo, and the depiction of those suffering soldiers in a series of watercolours (now in the Wellcome Library for the History and Understanding of Medicine): valuable experience for a writer on the expression of physical pain.

In his book The anatomy and philosophy of expression as connected with the fine arts, Bell argued that Laocoon as he is portrayed in the sculpture could not have roared like a wounded bull, not for the reasons proposed by Winckelmann or by Lessing but for anatomical reasons. The muscles needed to roar are those of the chest. But the chest is also the place where the muscles which have insertions in the arms, and which provide strength to the arms, have their fixed origin. When the arms are strenuously engaged, as Laocoon's certainly are, the ability of the chest to produce a roar, or any violent expiration, is compromised by the work which the chest is already doing for the arms. Hence, says Bell:

that most terrible silence in human conflict, when the outcry of terror or pain is stifled in exertion; for during the struggle with the arms, the chest must be expanded or in the act of rising; and therefore the voice, which consists of the expulsion of the breath by the falling or compression of the chest, is suppressed. The first sound of fear is in drawing, not expelling, the breath.

Therefore, Bell concludes, "Laocoon suffers in silence", not because to portray him otherwise would have robbed him of dignity, nor because what is permissible in a verbal representation was impermissible in a visual one, but because the sculptor's design was "to represent corporeal exertion, the attitude and struggles of the body and of the arms", an act which would have permitted nothing more than "a low or hollow groan".

A review of studies of the Laocoon show that, in the interpretation of human history, no single form of expertise by itself enables us to understand the past. If we were to allow ourselves to be constrained inside disciplinary frontiers marked 'History of medicine', 'History of art', 'Philosophy' or 'Psychology', we should be prevented from achieving the broad, integrative, context-rich understanding which history can generate when properly studied.

William Schupbach is Curator of the Iconographic Collections of the Wellcome Library for the History and Understanding of Medicine.