The British colony of Australia began in 1788 with the establishment of a penal colony at Port Jackson in New South Wales. Overcrowding in British prisons led them to send convicts to Australia, where they established a labor system using convicts to develop infrastructure and work for settlers. One of the strictest penal colonies was Port Arthur in Tasmania, established in 1830 to house hardened criminals re-offending in Australia. Conflict arose between British settlers and Aboriginal Australians, as settlers brought disease and guns while forcing surviving Aborigines onto interior reservations. Gold discoveries in 1851 attracted many new settlers and increased Australia's push for independence from Britain.