Contains one letter from the antiquarian John O'Donovan to George Petrie including a copy of the entry from the year 1484 from the Annals of the Four Masters (RIA MS 23 P 6). O'Donovan has written the relevant sections in Irish verbatim in insular minuscule script along with a translation in Latin and his commentary in English. O'Donovan glosses the entry, including an extended commentary on anchorites and the etymology of "cloch anchoire."

Possibly the oldest extant letter from John O'Donovan addressed to George Petrie.