International Judicial Monitor
Published by the International Judicial Academy, Washington, D.C., with assistance from the
American Society of International Law

Spring 2016 Issue

Historic Moments in International Law


The Very Fine Art of Oath Swearing

Stephen C. NeffBy: Stephen  C.  Neff, Reader in Law – Public International Law, University of Edinburgh Law School

As modern-day humanitarian lawyers well know, there is a world of juridical difference between ruses of war and perfidy.  A ruse lulls the enemy into a sense of false security.  It is, in effect, deception as to fact – and is perfectly lawful.  Perfidy, in contrast, deceives the enemy as to the prevailing legal state of affairs, i.e., it misleads the enemy into thinking that he is under the protection of the laws of war when in fact he is about to be attacked.  As such, it is severely condemned.

This sometimes subtle distinction can be traced far back in history.  The ancient Greeks, for example, were adept at ruses – most famously that of the Trojan horse – but they were scrupulous about respecting their legal obligations.  In particular, they took great care to avoid violating oaths solemnly sworn, even for the benefit of enemies.  At the same time, however, the Greeks – and other ancient peoples too -- were quite willing to engage in what might politely be called “sophistic” interpretations of their legal obligations.  Some would use harsher language.

The Roman historian Frontinus, for example, tells the story of an Athenian general named Paches, who induced his foes to lay down their steel (ferrum), in return for a promise that his army would do them no harm.  The enemy duly surrendered their swords – only then to be massacred, on the ground that they had violated their part of the deal by retaining the iron clasps on their cloaks.

Polybius disapprovingly relates the story of a group of Greeks from the city-state of Locris who were founding a colony in Sicily, in probably the late Eighth or Seventh Centuries B.C.  The local people, known as the Sicels, were worried – with good reason – that the Locrian colonists planned to expel them from their homeland.  The Locrians put them at ease by swearing that they would be friends with the Sicels and share the territory with them “as long as they trod on this earth and wore heads on their shoulders.”  The clever Greeks, however, at the very moment of the swearing, had carefully placed earth in their shoes, and had also concealed heads of garlic on their shoulders, under their cloaks.  Having thus reassured the Sicels of their good intentions, they then emptied the earth from their shoes (so that they were now treading on shoe leather rather than earth!) and threw the garlic “heads” off of their shoulders – and expelled the Sicels from the area.

In the late 6th Century, an intriguing – if slightly gruesome – incident is said to have occurred in Sparta.  King Cleomenes I, who was not in the regular line of succession, gained power with the assistance of a certain Archonides.  To express his gratitude, Cleomenes swore to Archonides to “do nothing without his head” – i.e., to consult Archonides on all major decisions in the course of his rule.  As a decidedly imaginative means of implementing this commitment, Cleomenes had his helpmate decapitated.  He then had the head embalmed, and carefully kept it ready to hand at all of his future state business.

The prize for creative interpretation of oaths should perhaps go to the women of the Greek city-state of Chia, when it was locked in armed combat against Erythrae, over possession of the city of Leuconia.  The Chians had the worse of the contest and finally agreed to surrender Lcuconia and to depart carrying only their cloaks and tunics.  The women of the city then conveniently recalled an ancient local custom, according to which a spear was labelled as a “cloak” and a shield as a “tunic.”  The soldiers apparently followed this advice and departed fully armed.

It should not be thought that the Greeks had a monopoly on sophistic interpretations of legal obligations.  We may award due points to the Phoenicians, in their negotiation with local African peoples over the founding of the colony of Carthage in the Ninth Century B.C.  The Phoenicians are reported to have sworn to the local rulers to acquire only as much territory as could be encompassed by an oxhide.  They then promptly proceeded cut the said oxhide into a very thin – and long – rope, which gave them sufficient territory to accommodate their famous city.

Herodotus relates the enlightening story of a siege, in about 518 B.C., of the Greek town of Barca, in North Africa, by Persian forces sent from Egypt (then part of the Persian Empire).  After a long period of operations, 


the Persian commander hit upon an ingenious solution. He dug a trench, laid thin boards over it and covered the boards with dirt so that, to the naked eye, it looked like an ordinary level patch of earth.  A peace conference was then held the next day – carefully staged so as to take place right over the hidden trench.  It was agreed that, in exchange for a reasonable payment by the Barcaeans, the Persians would lift the siege and depart.  The Persians confirmed the arrangement by solemnly swearing that the agreement would remain in force so long as the earth beneath their feet remained firm.  When the gates to the city were then thrown open, the Persians rushed in and captured the town – though only after pointedly exposing the hidden trench, so as not to stand accused of violating their oath.

In A.D. 51, as related by Tacitus, a city in Armenia was being besieged by a force from the neighbouring kingdom of Iberia (i.e., not the Spanish-Portuguese peninsula).  In the course of negotiations to end the siege, Rhadamistus, the son of the Iberian king, swore an oath that, if the Armenian leader,Mithradates, would surrender the city, Rhadamistus would do no violence to him by sword or poison. Mithradates, alas, failed to appreciate the limited nature of that commitment.  He was indeed killed – neither by sword nor poison, to be sure, but instead by being thrown to the ground and smothered.

The Romans were supposed to be different, given the emphasis that Roman law placed on good faith.  But good faith was apparently reserved for dealings with fellow citizens. A tale is told of how the Romans, after one of their many conflicts with the Samnites, were permitted to remove one row of stones from a Samnite defence wall. The cagey Romans then set about removing the bottom row rather than the top one – thereby bringing the wall completely down.  Not dissimilar was an arrangement that the Romans made with the Seleucid ruler Antiochus in the Second Century B.C.  Antiochus, after a decisive defeat, was to surrender half of his naval fleet to the Romans.  The Romans then decided that they preferred to carry this out by taking one-half of each Seleucid ship.

What is interesting about these various incidents – some of which admittedly seem more like music-hall gags than actual historical events – is that there is so little evidence of disapproval of them.  It was, apparently, widely regarded as being up to the beneficiaries of commitments under oath to be watchful as to the precise terms of the arrangement in question.  Not surprisingly, some states took care to include anti-deceit clauses in treaties that they concluded with other states – although this did not ever become a common practice.  One standard formula was to specify that treaty commitments were to be carried out “without trick.”  Alternatively, commitments were sometimes stated to be discharged “not with craft nor with stratagem.”

It would seem that the principal voices raised against sophistic interpretations of oaths and treaties were the stoic philosophers – fittingly, as they had a reputation for being earnest, strait-laced killjoys.  Cicero, who was influenced by stoic thought, voiced a suitably high-minded objection to such practices.  He gives as an example not to be followed, that of a general (tactfully unnamed) who swore to observe a truce of “thirty days” – and then proceeded to undertake his devastations by night.

In the Seventeenth Century, Hugo Grotius similarly expressed stern disapproval of sophistry in the interpretation of legal obligations.  Our modern law also takes this course.  Most notably, the Vienna Convention on the Law of Treaties requires treaties to be interpreted “in good faith.”  This brings some welcome confidence to bear on the process of treaty-making – though at the expense, it may be said, of a certain degree of entertainment.

For those interested in the wily doings of our classical ancestors, Frontinus (noted above) was the author, in the First Century A.D., of an informative book on The Strategems, which drew to some extent on his personal military experience.  Another useful handbook of strategems of war was written in the following century by a certain Polyaenus.  He strayed at times from his subject, to dispense welcome advice on such ever timely topics as “how to woo a tyrant’s daughter” and “how to force your relatives to give you money” – subjects of obvious utility.  For those who prefer a more sober and scholarly approach, the work to consult is Everett L. Wheeler, “Sophistic Interpretations and Greek Treaties” (1984), in volume 25 of Greek, Roman and Byzantine Studies (available in any well-stocked law library).  It made the research for this column a particular pleasure.

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