A collection of letters written by members of the society laboring in foreign missions, to their superiors and brethren in Europe.
The custom of writing such letters was based upon instructions given by Saint Francis Xavier to Joam Beira directing him to send to Ignatius in Rome, and Rodriguez in Lisbon "such news as when known in Europe would make every one that heard it give glory to God."
The letters were of three kinds: those of an intimate nature, to a relative, friend, superior or the Father General, not to be given publicity; letters to members of the society which were circulated in manuscript among the different houses; these were later revised and translated into Latin and extracts from them were published as ""; letters written for publication; this class is generally known as "Relations."
The most noted of these are the letters of the missionaries of New France, which have proved a rich source of information on early American history.
Parkman says, "They hold a high place as authentic and trustworthy documents," and draws heavily from them in his works, as do also Bancroft, Kip, Field, Dr. Finley and other historians of note.
Opening with the letters of Biard, 1616, the custom of writing the letters was brought to an end by the order of Pope Clement X forbidding missionaries to publish matter concerning the missions without permission of the Congregation for the Evangelization of Peoples.
Written under the most extreme hardships, their literary form is often crude, but the style is simple and direct, and the contents clear.
The complete edition in 73 volumes by Reuben Gold Thwaites includes an account of other well-known editions such as those of O'Callaghan, Shea, Reverend Felix Martin and the Canadian Government's reprint of the Cramoisy series, with information on libraries and collectors having editions of the originals.
New Catholic Dictionary