score:14
He was himself an escaped slave, so at the very least we know he was in favor of abolition of slavery in that one case.
We actually only have two writings from St. Patrick himself. Most of our material about him comes from other sources. So limiting yourself to just those two writings, while indeed much more historically sound, is a rather drastic limitation.
However, since there are only two, and they are public domain, the analysis isn't tough to do.
This mentions slavery as it pertains to himself several times, but nothing useful about it in general.
A Letter to the Soldiers of Coroticus -
I think the following passage strongly implies that he considers making slaves of Christians and anyone who wasn't born into that condition to be immoral:
For they have been taken far away and abandoned in a land where sin abounds, openly, wickedly, impudently; there freeborn men are sold, Christians are reduced to slavery, and worst of all among the most worthless and vilest apostates, the Picts
But again, these are the only two surviving examples of his writing. We know of more from his biographers, plus many speeches and sermons that did not get written down at the time. There is even some known early third-party biographical material that has been lost (eg: The Book of UltΓ‘n). This material is all inferior to the above two first-hand accounts of course, but in History, particularly Medieval history, you have to do the best you can with what little you have.
Upvote:1
At the very least, we can say that Patrick thought that people being enslaved was a bad thing.
Patrick wrote two surviving works. One of them was the Confessions, another was titled A Letter to the Soldiers of Coroticus. In the latter, Patrick notes in a very displeased manner that βFor they have been taken far away and abandoned in a land where sin abounds, openly, wickedly, impudently; there freeborn men are sold, Christians are reduced to slavery, and worst of all among the most worthless and vilest apostates, the Pictsβ. In the former, the Confessions, Patrick speaks more generally about slavery when he says that "Those who are kept in slavery suffer the most." This suggests that Patrick is not a very happy person about the idea that people are kept in slavery.