The legal system of Australia has multiple forms. It includes a written constitution, unwritten constitutional conventions, statutes, regulations, and the judicially determined common law system. Its legal institutions and traditions are substantially derived from that of the English legal system. Australia is a common-law jurisdiction, its court system having originated in the common law system of English law. The country's common law is the same across the states and territories (subject to augmentation by statutes). The Australian Constitution sets out a federal system of government. There exists a national legislature, with a power to pass laws of overriding force on a number of express topics. The States are separate jurisdictions with their own system of courts and parliaments, and are vested with plenary power. Some Australian territories such as the Northern Territory and the Australian Capital Territory have been granted a regional legislature by the Commonwealth. The High Court is Australia's apex court. It has the final say on the judicial determination of all legal matters. It hears appeals from all other courts in the country, and is vested with original jurisdiction. Prior to colonisation, the only systems of law to exist in Australia were the varied systems of customary law belonging to Indigenous Australians. Indigenous systems of law were deliberately ignored by the colonial legal system, and in the post-colonial era have only been recognised as legally important by Australian courts to a limited degree. History Law prior to Colonisation Indigenous Australian customary law varied between language groups, clans, and regions. It developed over time from accepted moral norms within indigenous societies. The laws regulated human behaviour and relationships, mandated sanctions for misdeeds, and connected people with the land and each other through a system of relationships. Such law is often intertwined with cultural customs, stories, and practices. These customs were and are passed on intergenerationally through oral tradition, often incorporated within cultural works such as songlines, stories and dance. Arrival of English law through colonisation The English legal system was introduced to Australia through colonisation. Upon arrival to Australia, the colonists declared that the laws of England were to immediately apply to all settled lands. This declaration was asserted by reliance upon a legal fiction that the Australian continent was terra nullius; i.e. land belonging to no-one, as it was believed that the Aboriginal peoples already inhabiting the continent were not cohesively organised for a treaty to be