Facts about Petard


Fact: A petard was a useful military device for breaking down gates!


In modern English, the quote from Hamlet “hoist with his own petard” can still be heard as an idiomatic expression. For the most part the original meaning has been lost, due to petards not being encountered frequently in modern life. For hundreds of years petards were a necessary explosive device used to break into fortresses and other barred gates.

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Breaking Wind: Dangerously

Originating in 16th century France, petards are explosive devices used to break through doors, gates, and in some cases walls. Manuscripts from the renaissance detail that most petards were either rectangular or roughly cylindrical in shape, which were filled with 4-6 lbs of gunpowder. The device would then be attached directly to the door or wall using a wooden brace called a madrier, and then lit using a slow match. Although ultimately crude and inconsistent in results, the petard was nevertheless an important part in attacking fortifications and sieges from the 16th-19th centuries. The name came from the French word “péter” which at the time meant to break wind (or fart). This naming was likely due to the noisy and violent action of a petard in use.


By the turn of the 17th century petards were ubiquitous in the militaries of England and continental Europe. The use of petards was usually handled by engineers (what would now be referred to as “military engineers”, or those soldiers responsible for the use of siege engines). However due to the unpredictable nature of the petard, and the highly volatile gunpowder attempts to light the explosive often failed or lead to the death of the person operating the device. This background illuminates the famous line written in Hamlet by William Shakespeare in 1602.

In Act 3 Scene 4 Hamlet discovers a plot to have himself killed by conspiracy of his Uncle Claudius the King of Denmark. Claudius sends Hamlet with two of his schoolfellows to deliver a letter to the King of England. The letter secretly instructs the King to execute Hamlet; however on the voyage Hamlet secretly opens the letter and decides to re-write it to instruct the execution of his conspiratorial friends. He offers the following quote:

There’s letters seal’d: and my two schoolfellows,
Whom I will trust as I will adders fang’d,
They bear the mandate; they must sweep my way
And marshal me to knavery. Let it work;
For ’tis the sport to have the enginer
Hoist with his own petar’; and ‘t shall go hard
But I will delve one yard below their mines
And blow them at the moon: O, ’tis most sweet,
When in one line two crafts directly meet.

In the language of the time “hoist” would refer to being lifted up, in this case by way of an explosion of the petard. Thus Hamlet marvels that his enemies attempts to undermine him, will backfire and cause their demise. In modern English one who is “hoist with his own petard” refers one who is injured by a device intended for injuring others (i.e. when a plan against another backfires). Thus the intention of the original phrase is not lost, although the vocabulary used has lost much of its frame of reference.

Persistence into the modern age

As gunpowder manufacturing and applications improved, petards continued to be employed and improved in designed. Examples from the 19th century are found to be well constructed using metal bracers for the madrier, and very finely positioned charges. Eventually, field artillery and high explosives proved so effective at destroying fortifications from afar, that the use of petards in military siege began to wane. By the start of the 20th century their role had been replaced by shape charges and other more effective explosives. However the name persisted for a time during World War II. A modification to the British Churchill tank used a specialized short-range high explosive mortar which could be used to breech fortifications. This cannon was referred to as the “flying dustpan” or the AVRE’s Petard Mortar.

To see examples of historical Petards click on the following: