Each society defines what human conduct is tolerable and what is not. Many rules about behavior are socially enforced as unwritten customs. For instance, a person wearing inappropriate clothing may be shunned or ridiculed. More serious offenses are subject to written laws. As seen in historical images, breaking a law results in punishment, which may be as mild as public humiliation or as severe as the death penalty. Because a code of conduct is based on moral and ethical values, the history of laws is closely linked to social history, such as the history of religion. Arrests and trials have been part of the judicial system in some form since the time of classical civilizations, as seen in historical illustrations, along with courts and judges. Attorneys are professional advocates replacing the direct confrontation between the accuser and the accused.
Important milestones in legal history include the Codex Hammurabi in ancient Babylon, the English Magna Carta, and the American Declaration of Independence as well as the US Constitution. However, not all laws are systematically written, or codified. English common law, for instance, is based on precedent--the accumulated legal outcomes of similar cases that have been adjudicated. Changes in laws may happen gradually as societal values change, or legal changes may be enacted at a point in time, such as constitutional amendments in the US. Sometimes a single individual may change a law; for instance, the Emancipation Proclamation, effectively abolishing US slavery, was issued by President Lincoln based on his executive authority. A change in regime may also bring about changes in the laws of the land, for example, the expulsion of the Acadians from Canada after the British captured French Canada in the 1700s.
Enacting laws to keep members of a society healthy and safe is one job of government. Law enforcement is a related and important function. The form of government affects what laws are enacted as well as how they are enacted and enforced. As seen in historical pictures, monarchy has been the dominant form of government in history, which includes all hereditary rulers such as kings and queens, pharaohs, sultans, and tsars. Other leaders have arisen on merit, such as Native American chiefs or military conquerors who then became administrators of acquired territory. More recently parliamentary governments are the norm, including those with democratic elections to choose legislators who enact laws. The head of state may be an elected president or an appointed prime minister or other official.
As seen in historical pictures, what constitutes a crime has been defined differently among different cultures and has changed over time within a single society. Religious beliefs often shape societal views about crime. The Ten Commandments comprise a well-known example of early laws formed by religion. Having a different belief than the prevailing religion is called heresy, and throughout history, heresy has been a punishable offense in many cultures. The same forces that define crime, define punishment. Capital punishment is usually reserved for offenders whose crimes pose a serious threat to the society, such as treason or murder. In some cultures, punishment may be very mild for rape, while even a minor theft may warrant death; in other cultures, these values may be reversed. Some societies prosecute witches, and other societies do not recognize witchcraft as a crime.
Historical pictures of lawlessness show how innocent citizens may be subjected to harm by mob violence and other dangerous situations from vigilantes or outlaws in the absence of due process offered by courts and law enforcement. As historical pictures show, mobs are also prone to be directed in the heat of anger by their members' prejudices rather than by considered facts. Warfare is another situation in which most societal laws do not prevail, and civilians may become refugees or victims of violence generated in the upheaval of battles and by armies' fear and hatred of the enemy.
Relations between countries are governed by international treaties, which are mutually binding laws that create military alliances or address economic issues between nations, such as a trade embargo. As vintage images show, when conflict arises between countries, the usual solution involves military force, from a naval blockade to outright war. Peace treaties formalize a ceasefire and terms of victory after a surrender.