Why can’t you find your ancestors?
Absence of evidence is not evidence of absence. Which is to say that trying to explain why you can’t find an ancestor is akin to collecting water in a sieve. But here are a few possibilities anyway:
At the precise moment the National Library was microfilming the parish register page with your ancestor on it, a tiny wink of light crept through the blackout curtains and fell on just the last few letters of the surname, creating a small overexposure and making the name eternally illegible. This has actually happened to me. How do I know, (asks the smart boy at the back), if the name was illegible? Because a heritage centre had made a separate transcript from the same register. Hurrah for duplication of effort.
That heritage centre had excellent parish register transcriptions, with a rate of error as good as possible, less than 2%. Guess who falls into that 2%? That’s right, your other line of ancestors. Back to grinding through the microfilm.
But why can’t you find your family in the 1901 and 1911 censuses at census.nationalarchives.ie like everyone else? Perhaps because the transcribers used the existing paper finding aid as a guide to place-names. Some smallish towns were inside neither a townland nor a proper urban area, and fell between two stools. For paper this didn’t matter – the exceptions were just stuck in manually. But computers don’t do exceptions very well. Parts of at least 20 small towns – among them Moate, Ballygar, Lanesboro, Castledermot and Mullinahone – were simply never transcribed.
And of course you have to consider the possibility that you have no ancestors. There are a small number of cases where individuals simply pop out of the universal quantum foam without forebears, already fully formed and usually wearing a suit. Most of them seem to be in political parties.