Early 19th century; earliest use found in Sydney Morgan (bap. 1783, d. 1859), novelist and socialite. Originally from Irish céad míle fáilte a hundred thousand welcomes from céad hundred + míle thousand (Early Irish míle from classical Latin mília, mílle: see milli-) + fáilte welcome. In some later uses from the corresponding phrase in Scottish Gaelic, ceud mìle fàilte.