resulting in many mass-killings. In November 1826 Governor Sir George Arthur issued a government notice declaring that colonists were free to kill Aboriginal people when they attacked settlers or their property and in the following eight months more than 200 Aboriginal people were killed in the Settled Districts in reprisal for the deaths of 15 colonists. After another eight months the death toll had risen to 43 colonists and probably 350 Aboriginal people. In April 1828, Arthur issued a Proclamation of Demarcation forbidding Aboriginal people to enter the settled districts without a passport issued by the government. Arthur declared martial law in the colony in November that year, and this remained in force for over three years, the longest period of martial law in Australian history. In November 1830 Arthur organised the so-called "Black Line", ordering every able-bodied male colonist to assemble at one of seven designated places in the Settled Districts to join a massive drive to sweep Aboriginal people out of the region and on to the Tasman Peninsula. The campaign failed and was abandoned seven weeks later, but by then Tasmania's Aboriginal population had fallen to about 300. Removal of Aboriginal people After hostilities between settlers and Aboriginal peoples ceased in 1832, almost all of the remnants of the Indigenous population were persuaded or forced by government agent George Augustus Robinson to move to Flinders Island. Many quickly succumbed to infectious diseases to which they had no immunity, reducing the population further. Of those removed from Tasmania, the last to die was Truganini, in 1876. The near-destruction of Tasmania's Aboriginal population has been described as an act of genocide by historians including Robert Hughes, James Boyce, Lyndall Ryan and Tom Lawson. However, other historians including Henry Reynolds, Richard Broome and Nicholas Clements do not agree with the genocide thesis, arguing that the colonial authorities did not intend to destroy the Aboriginal population in whole or in part. Boyce has claimed that the April 1828 "Proclamation Separating the Aborigines from the White Inhabitants" sanctioned force against Aboriginal people "for no other reason than that they were Aboriginal". However, as Reynolds, Broome and Clements point out, there was open warfare at the time. Boyce described the decision to remove all Tasmanian Aboriginal people after 1832by which time they had given up their fight against white colonistsas an extreme policy position. He concluded: "The colonial government from 1832 to 1838