Patrick was probably from Dublin Ireland.There are old family stories to the effect that he was serving in the Kings Waiters (a British military unit that in Ireland guarded the prisons and the customs house).He did not like it and took passage on a ship for America.(He probably shipped to Glasgow and thene to America)Legend suggested that he landed in Virginia but he was indentured and there is a record of a Patrick "Smith" indentured the right time in Philadelphia.The man who purchased his indenture (and here we are at last on pretty firm historical ground) was Ulrich Conrad, a Swiss Mennonite settled in Pendleton County who took Patrick down to Pendleton and put him to work doing whatever in 1773.Pretty quickly Patrick was called upon to do military service.I doubt Ulrich's beliefs permitted him to do so and I think Patrick went on the Point Pleasant expedition (which drew heavily on settlers from that area) in Lord Dunmores war in 1774.Patrick had been at least minimally militarily trained by the British (which made him a suitable comrade in terms of stamina and courage under fire to the mountain men and militia men who he accompanied to Ohio.
When hostitilites broke out in earnest in 1776 he signed up for two or three attested hitches and at some point either through Ulrich's generosity or clemency or an edict by the new government, his intenture disappeared.I am pretty sure he did not serve out seven years of indenture.He was at Yorktown and claimed he fired the last fatal shot before the truce (In cinema that was fired by Ned Dob (Dexter Fletcher) son of tracker and reluctant patriott Tom Dob (Al Pacino) in the movie Revolution (1985)when Ned shot and killed the foster son of the British officer (Donalds Sutherland) who had tormented him as a forced British conscript when he was younger.[a little trivia sometimes livens the story]It is always a little tricky to try to guess at the sympathies of people coming out of Ireland in that period.The suppression of the Jacobites was not that long past and only Protestant Irish (the occasional native convert or the more numerous Scotch Irish) were typically allowed to settle in the colonies.Our Patrick is a bit of a mystery on that score.He is said to have noted he was named for Saint Patrick because he was born in St Patrick's day but can we really be sure what he was to start with or what he became and how? The lines in Ireland have always been a bit murky.
Our real Patrick was then married to Catherine Hevener and the Heveners were I am pretty sure Reformed Calvinist (They were briefly up in Berks PA) but by this point the finer points of religious doctrine may not have been the driving force in young Patrick's life.
As to Dublin itself, I have seen evidence of two Sinnett families (though perhaps they are the same) one of which had a Catherine Sinnett who married a Robert Cunningham (Scotch Irish) living there brother to a Cunningham whose descendant married one of Patrick's children in Virginia.I think I wrote on this in an earlier post in this forum.
The other family was the family of Mark Sinnett who was a sheriff or similar official in Dublin in the late 1700's.Whether this family was Church of Ireland or Roman Catholic is murky though Church of Ireland seems more likely.The information I have found on the family as yet is murky.There are several generations extant and the family still exists as far as I know.It is probably in the peerage, I have not looked.Our Patrick does not seem to have been from the main branch of this family at least because he would not then have been doing guard duty at a prison.Last I was in Dublin I visited the Michael Collins barracks (the old Royal Army Barracks) in West Dublin that have become a museum of Irish military men and women through the ages but unfortunately the woman who was best informed as to the particulars of the Kings Waiters and who could have pointed me at the records was on holiday.A task put aside for another day.