Flag of the Southern Cross is a poem written in 1887 by Australian bush poet Henry Lawson. The "Flag of the Southern Cross" refers to the Eureka Flag flown at the Eureka Rebellion in Ballarat, Victoria in 1854. A copy of the poem can found at http://www.ironbarkresources.com/henrylawson/FlagOfTheSouthernCross.html.
The victory song of the Australian cricket team—Under the Southern Cross I Stand—is said to have been inspired by this poem.
References
Flag of the Southern Cross Wikipedia(Text) CC BY-SA