A kangaroo court is an illegal form of rough justice usually presided over by an unruly mob. Despite its obvious Australian connotations, the phrase is of American origin and its first appearance is in the newspaper The Mississippian 12 January 1839. For a phrase to appear in print, it must have been in prior use in speech. Therefore, its spoken origin must pre-date 1839. At about the same time, in America, kangaroo courts were also known as mustang courts. The unpredictable behaviour of kangaroos and wild, untamed horses obviously has a bearing on the naming of these so-called courts.