If everybody that claims to be 'basically, Irish' really is, then it's hard to believe the rest of the world was inhabited two hundred years ago. Like the true cross, there seems to be rather more of it about than is quite plausible.
But the Irish National Archives has now put the full 1901 census online, covering 4.5 million individual people in 850,000 households across the country, hopefully enabling people to back up their claims.
"The Irish diaspora is estimated to amount to 70 million people in all parts of the globe, and many of these have an interest in their family and local history," it says.
The records list each person's name, age, sex, relationship to head of the household, religion, occupation, marital status and county or country of birth. The census also records an individual’s ability to read or write and ability to speak the Irish language.
The website can be searched on almost any set of terms, from name to occupation or even illnesses.
James Joyce features, then a 19-year-old student living with his family in Dublin. CS Lewis was there too, as a two-year-old, and Edward (Eamon) de Valera is listed as an 18-year-old student at Blackrock College.
The project has taken five years and cost nearly Eur4 million.
The 1911 census was put online in 2009, and has attracted more than 250 million hits. But 1901 looks set to be the earliest record ever available, as nineteenth-century records were all either lost in a fire or pulped during a paper shortage.