The history of modern Roman Catholic Missions to heat en countries forms an important subject of inquiry with all who take an interest in the progress of Christianity. One of the most remarkable periods in this history is that which extends from the middle of the sixteenth to the middle of the seventeenth centuries. It was then that Jesuit Missionaries and some of the ablest men appeared in the field. The great influence and wealth of Portugal were at that time exerted to give effect to the work of evangelizing India, Japan, China, and America. It is difficult to calculate the number of Missionaries which the Church of Rome maintained during that period in all parts of the known world. Long after the work had declined, by the expulsion of the Portuguese from their Eastern supremacy, Niecamp, who wrote a History of the Danish Mission in South India, states, that when the first two Protestant Missionaries were sent out (in 1706), the number of Romish Missionaries then in the East was estimated at two thousand.

Yet our information of Roman Catholic Missions is very meagre and unsatisfactory. The sources of information are either various collections of letters of Missionaries, or dry compilations from those letters. But these sources of information cannot satisfy any one who desires a clear knowledge of this subject. He will seek for histories of Missions written from the field of labour by the labourers themselves, or by those who have witnessed the work abroad: or the Journals and collected letters of individual Missionaries.