The six Australian colonies united on 1st January 1901 to become the Commonwealth of Australia. One of the reasons given for this federation was that the Commonwealth could provide a common defence.William Rooke Creswell argued that, as an island continent, Australia could not defend itself without a navy. He saw no point in having a 70,000 strong army if only one enemy battleship could destroy port cities and disrupt maritime trade and sea communications.Creswell was not alone in his campaign to establish a navy for Australia but he was the one constant advocate throughout the years from his first proposals on a navy for Australia in 1886 to when the first ships of the Australian Fleet sailed into Sydney Harbour in October 1913.