Common law is a type of legal system that relies heavily on precedents developed by judges and court cases, rather than legislature. Although legislative statutes have a prominent place in the legal system, it often occurs that the public and law official will disagree and interpret statues differently. That is why it can be very beneficial to turn to the past decisions of judges in cases of similar circumstances.
In cases of unique circumstances where there is no former precedent, called matters of first impression, a judge will create case law by ruling in a way that will effect all future cases of similar circumstances. The most important concept of a common law system is that cases that are considered to be similar in circumstance to prior cases should result in the same ruling by the court. It is sometimes referred to as case law because it is built upon the results of individual cases.
The system of common law first developed in England after the Norman Conquest of 1066. The kings desired to unify the legal system and replace the multitude of individual systems that governed each small county. In the 12th and 13th centuries, as the Normal Inquest became to overtake the legal system, judicial decisions were being recorded and a system of custom and precedent began to take shape. Distinct from criminal law, the common law system was used to decide tort cases where a plaintiff accused the defendant of some wrongdoing and requested compensation for his injuries.
It was also during this time that court cases began to be decided by judges and juries. King Henry II played a large role in abolishing the area-specific law and establishing a system of common law, as well as ending many of the outdated punishments for crimes.
Common law systems work well in deciding court cases based on civil torts, contract law, and property law. These types of law do not exist in legislature and instead exist entirely in common law. However, this is not usually the procedure in deciding criminal cases. Criminal law is deeply related to legislative statutes. In order for the general public to be aware of what types of activity is considered criminal, the courts have decided that it is only fair for this activity to be formalized in legislative statute.
In the United States, this has been the basis of criminal law since 1812. Legislative statutes in criminal law offer punishments for wrongdoing that are different from punishment based on common law. Punishment for criminal offenses attempt to cause suffering to the criminal as will as deter him from committing future crimes.