Now it was a very ancient custom among Christians to recite at the most sacred part of their most sacred service (in the so-called Canon of the Mass, immediately before the consecration of the Host) the names of deceased saints and martyrs. Religious men of local celebrity were inserted for this purpose in local lists, called Diptychs, and names universally honoured throughout Christendom appeared in all such catalogues. The confessors and martyrs so honoured are now said to be _canonized_, that is, they have become enrolled among the number of Christian saints mentioned in the ‘Canon,’ whom it is the duty of every Catholic to revere, whose intercession may be invoked, who may be chosen as patron saints, and in whose honour images and altars and chapels may be set up.[45] For a long time it was permitted to the local ecclesiastics to continue the custom of inserting such names in their ‘Diptychs,’ but about 1170 a decretal of Pope Alexander III. confined the power of canonization, as far as the Roman Catholics were concerned,[46] to the Pope himself. From the different Diptychs various martyrologies, or lists of persons so to be commemorated in the ‘Canon,’ were composed to supply the place of the merely local lists or Diptychs. For as time went on, it began to be considered more and more improper to insert new names in so sacred a part of the Church prayers; and the old names being well known, the Diptychs fell into disuse. The names in the Martyrologies were at last no longer inserted in the Canon, but are repeated in the service called the ‘Prime’; though the term ‘canonized’ was still used of the holy men mentioned in them. And when the increasing number of such Martyrologies threatened to lead to confusion, and to throw doubt on the exclusive power of the Popes to canonize, Pope Sixtus the Fifth (1585-1590) authorized a particular Martyrologium, drawn up by Cardinal Baronius, to be used throughout the Western Church. In that work are included not only the saints first canonized at Rome, but all those who, having been already canonized elsewhere, were then acknowledged by the Pope and the College of Rites to be saints of the Catholic Church of Christ. Among such, under the date of the 27th of November, are included “The holy Saints Barlaam and Josaphat, of India, on the borders of Persia, whose wonderful acts Saint John of Damascus has described.”[47]