Digger History, the Unofficial history of the Australian & New Zealand Armed Services, says of Foo that "He was chalked on the side of railway carriages, appeared in probably every camp that the 1st AIF World War I served in and generally made his presence felt".[1] If this is the case, then "Foo was here" predates the American version of World War II, "Kilroy was here", by about 25 years.