Seapatrick is the area where Banbridge is situated in County Down. Joseph Scriven was born at Ballymoney Lodge (just off today's A1 carriageway, where it meets the A26 or Dromore Street roundabout) on 10 September 1819. His life story is remarkable. In 1845 he emigrated to Canada. His musical contribution to the world was the hymn What A Friend We Have in Jesus which he wrote the words of in 1855. He was accidentally drowned in a millpond and was buried at Bailieboro, Cavan County, on the shores of Rice Lake (source here). Interestingly, there is also a Bailieborough in County Cavan in Ulster, so-named after the Bailie family from Scotland who had moved there from County Down. What A Friend We Have in Jesus is one of the world's most famous hymns, and has been translated into many different languages.
John O'Neill was born in the same area around 1837. He collected a huge repertoire of fiddle tunes, as detailed in Nigel Boullier's book Handed Down which was published last year. John taught his children to play the fiddle and left his collection of tunes to his son James. James O'Neill appears in the Catholic baptismal records in Seapatrick RC parish in 1862, but he emigrated to Chicago in 1881. He assisted Francis O'Neill to publish O'Neill's Music of Ireland in 1903, contributing about 21% of the tunes for that landmark publication.
Both men had a huge musical impact on the world - James O'Neill helped define the Irish traditional genre, and Joseph Scriven wrote one of the most famous hymns of all time. Not bad for a wee townland in County Down.
Ella Fitzgerald's version is at 22:20 in the video below.