Why does Sasana not use the definite article here? (Sa Sasana instead of i Sasana)
There's a few countries that aren't definite. Out of commonly used ones (from an English speakers point of view), they are: Ireland, Scotland, Canada, America, England.
In English examples with definite articles exist (The Netherlands, The Ukraine, ...). After a bit of googling, it seems like there are various etymologies behind them. I wonder if it's similar in Irish.