The League of Nations was the fore-runner to the present United Nations.
The Treaty of Versailles, including the Covenant of the League of Nations was signed on 28 June 1919 and was the first political treaty signed by Australian officials since Federation. A history of the signing, along with an explanation of the significance of the document is available at the website Documenting a Democracy.
From Signing the Treaty of Peace at Versailles, Sunday Times (Sydney, NSW : 1895 - 1930), Sunday 18 January 1920, page 20
Reports of the Australian delegation to the League, and reports submitted to the League, are reprinted in the Australian Parliamentary papers and can be found through the First consolidated index to the papers presented to Parliament 1901-1949.
The League oversaw the Permanent Court of Justice, and several other agencies and commissions were created such as the Health Organization, International Labour Organization, and Permanent Mandates Commission.
In 1946 the League of Nations was dissolved by a resolution of the 21st Assembly. Assets, property and some functions and roles were transferred to the United Nations.