[EvilGrin]

If this was in England it may of been an extended priest hole to hide Catholic Priests after the reformation. If there was an entire chapel hidden away it may of been for said priest to conduct mass for the Catholic household in secret.

https://en.wikipedia.org/wiki/Priest_hole

[Macha]

In this case it's in Ireland, but since it was under English control at the time, it would likely be the same.