Law is a system of rules that society or a government develops in order to deal with crime and business agreements and to manage social relationships. It also refers to the people who work in this system.
Legal systems vary from country to country and even within a single nation. However, they tend to fall into groups that have some similarities based on historically accepted justice ideals. Many countries employ more than one of these systems at the same time to create a hybrid system.
The primary sources recognised as authoritative are, primarily, legislation–especially codifications in constitutions or statutes passed by government–and custom. The latter dates back millennia, and some of its rules were compiled into Roman codes whose texts were rediscovered in medieval Western Europe. The legal practice of the era of the Roman Republic and Empire was heavily procedural, and it lacked a professional legal class.
In modern times, there are numerous international laws and treaties that attempt to set standards for global governance. These include respect for human rights, rule of law, separation of powers and participatory democracy. The rule of law enshrines principles such as supremacy of the law, equal access to courts and public services, impartiality in adjudication, fairness in the application of laws, independence of the judiciary, transparency, accountability and participation in decision-making. These are essential to a well functioning democracy and the protection of civil liberties and economic opportunity for all citizens.