A remarkable person. Her sister too.
Were these two quite anomalous at the time?
Not at all. Quite common in fact.
Are there many Protestants in Irish nationalist parties today?
In the south, there are protestants in all walks of life and at the moment quite a high rate of conversions to Anglicanism. The North is somewhat polarised.
Her life was an amazing story. On a side note (a Russia rather than a Poland thing), am I right in thinking that the most important part of the Russian crown jewels, the Cap of Monomakh, spent a few years in a cardboard box in someone's attic in Dublin?