It was planned around 1900, and "the Sydney–Melbourne rivalry was such that neither city would ever agree to the other one becoming the capital. ...Eventually,

It was planned around 1900, and "the Sydney–Melbourne rivalry was such that neither city would ever agree to the other one becoming the capital. ...Eventually, a compromise was reached: Melbourne would be the capital on a temporary basis while a new capital was built somewhere between Sydney and Melbourne." https://en.wikipedia.org/wiki/History_of_Canberra#20th_century https://en.wikipedia.org/wiki/History_of_Canberra#20th_centu...