Listening to Handel's Messiah tonight as part of our Advent celebration, my lovely wife mentioned ("Oh, by the way"), when she was in Ireland she saw an original manuscript of the Hallelujah Chorus in Dublin.
Turns out, Handel premiered the Messiah in Dublin a whole year before it came to London! He used a combined choir from the Catholic St. Patrick's Cathedral and the Protestant Christ Church. They jammed 700 people into the seats on opening night, asking attendees not to wear swords or hoop skirts. Read more about it here.