Torture is the infliction of pain on another person against their will. This is not necessarily the same as causing that person harm: it is meant to stimulate the pain centres of the brain of the victim. It is a simple concept and can be easily done to someone who is restrained or shackled. Despite this simplicity, it exists in a profusion of forms across most of the ancient cultures of the world and has played a prominent role in world history up to the current day.
Thousands of ancient torture methods existed and likely many more forms of torture were improvised at the time and simply went undocumented. They can be divided into three categories. There is psychological torture. By binding the victim tightly and making him feel helpless and alone, one can cause a great deal of mental anguish, panic, and hysteria without doing any actual physical harm to the victim. There is destructive torture. By mutilating, breaking, or amputating parts of the victim's body, one not only causes great pain, but also causes the victim to feel great despair and sadness in the knowledge that they will never be whole again. There is optimised torture. This utilises instruments and techniques to stimulate the pain receptors in the body as much as possible without causing much in the way of outward physical damage.
Torture has existed long before the medieval period, the time where so many torture implements were developed and used. The first records of torture came from Egypt, where people who were considered untrustworthy were whipped by means of interrogation when a crime had been committed. It was commonly used in the legal process in Rome and Greece as well. At the time these methods of torture were very simple. Often the victim was tied and suspended from a post and then whipped mercilessly. Simultaneously, psychological torture and more creative ways of inflicting permanent harm and injury on people were being used in the various provinces that make up modern China.
The various methods of torture did not change all that much until reports of how prisoners of war and criminals were being treated began to flood back to Western Europe from the Middle East during the crusades. These methods of torture had in turn been inherited by the Middle East from the Far East. From the crusades, much of this knowledge on how to inflict pain was passed on to Europe.
Rather than use the sparse, labour-intensive methods that were common in the Middle East, many of the European countries developed machinery to do the work for them. These implements of torture were used for many purposes by many official agencies until the end of the Victorian era.
Current methods of torture that are used today for the purposes of an agency or illegal group will focus on causing as much pain with as little damage as possible while including a psychological effect. A good example of this is the practice of water boarding.
A bag is placed over the head of the victim, who is strapped on a board which is inclined so his head is lying at a level lower than his feet. His torturers then pour water of the top of the bag, making it conform to the shape of the victim's head and face. This simulates the experience of drowning and is considered one of the most effective methods of interrogation today.
Torture has many different functions. For sadistic criminals it serves its own purpose in causing the victim unbearable pain. It was and is still used as an interrogation tool. It was used to force a confession of guilt from supposed criminals during the medieval period. The Catholic church used torture both to force confessions to crimes against the church from suspected heretics as well as to force suspected witches, warlocks, and Satanists to repent for their sins.
Perhaps the most effective function torture served was as a punishment for criminals. Instead of being locked away in a prison for decades on end, a criminal who had committed a crime that was not grounds for execution was sentenced to a type of torture for a period of time. Often a whipping or scourging was used. The form of torture as punishment people might be most familiar with is being placed in a pillory or stocks.
A common misconception among people today is that many of the medieval devices one sees in a torture chamber such as the iron maiden were intended to torture the victim. This is not so. They were intended to execute the victim in as slow and painful a process as possible. As horrible as this may sound, it was quite common for someone who was sentenced to death to be killed in this fashion rather than publicly executed by hanging or beheading. At the time such public methods were considered to be merciful forms of death to be used upon petty criminals and those who had been cooperative with the authorities.