St Patrick's Breastplate: original text
A correspondent has kindly passed on from her a link to the original Old Irish version of St Patrick's Breastplate from George Petrie's papers On the History and Antiquities of Tara Hill. The papers were given in 1837 and included in Volume XVIII of the Transactions of the Royal Irish Academy published in 1839.
The above image is a screen grab from one of the pages (click to enlarge).