Australia: Polity Style: 1901-2026

1 Jan 1901	the colonies of New South Wales, Victoria, South Australia, Queensland, Tasmania, and Western Australia constituted a federal commonwealth under the name of the Commonwealth of Australia on 1 Jan 1901, the date appointed by a proclamation issued by command of the Queen of the United Kingdom of Great Britain and Ireland on 17 Sep 1900 under an act passed by the Parliament of the United Kingdom (House of Commons on 25 Jun 1900, House of Lords on 5 Jul 1900, received royal assent on 9 Jul 1900) (Public General Acts, 1900, pp. 24-45; Australia Government Gazette, No. 1, 1 Jan 1901, p. 1) [1][2]
1 Jan 1901 -	Commonwealth of Australia
9 Oct 1942	the legislative independence of Australia from the United Kingdom is achieved upon the adoption of provisions of the Statute of Westminster, 1931, in accordance with the Statute of Westminster Adoption Act 1942 passed by the Parliament of the Commonwealth of Australia (House of Representatives on 8 Oct 1942, Senate on 9 Oct 1942, received royal assent on 9 Oct 1942, retroactively effective from 3 Sep 1939) (Australia Session Laws, 1942, pp. 181-184) [3]

Full title: An Act to constitute the Commonwealth of Australia (may be cited as the Commonwealth of Australia Constitution Act).
The colonies of New South Wales, Victoria, South Australia, Queensland, and Tasmania agreed to unification by the time of passing of the Commonwealth of Australia Constitution Act. Western Australia was added to the constituting members of the Commonwealth following a referendum held on 31 Jul 1900.
Full title: An Act To remove Doubts as to the Validity of certain Commonwealth Legislation, to obviate Delays occurring in its Passage, and to effect certain related purposes, by adopting certain Sections of the Statute of Westminster, 1931, as from the Commencement of the War between His Majesty the King and Germany (may be cited as the Statute of Westminster Adoption Act 1942).