Complex sentence: His article on the "History and Antiquities of Irishtown and Kilkenny", published in 1781, was appended to the second edition of his "Antiquities of Ireland", 1804.
Split into simpler sentences: His article on the "History and Antiquities of Irishtown and Kilkenny" was published in 1781. The same article is appended to the second edition of his "Antiquities of Ireland", 1804.