The ninth chapter of the ninth decade relates the work in the new field of Mindoro. The mission work of that island (of which and its people a brief description is given) is first begun by the Augustinians, who cede the district to the Franciscans. Later the Jesuits maintain a number of missionaries there and found the permanent mission of Naojan, which is maintained until Luis de San Vitores goes to the missions of the Ladrones or Marianas, when the island is turned over to three seculars. The district is a poor one, and the seculars, although zealous in their duties, cannot be adequately supported. Finally in 1679, as related above, the Recollects, after their glorious record in the Philippines and their flourishing mission work in the Zambal district, take up the Mindoro mission field, after a vain protest at being ousted from their Zambal missions. The transfer is speedily concluded by chaplaincies being provided for the seculars, and the Recollects, taking possession of the new territory, immediately put six religious to work. The new leaver is felt instantly and the number of Christians increases from 4,000 in 1679 to 8,000 in 1692, and to 12,000 in 1716. Although the Moro depredations lessen that number later, in 1738, San Antonio still chronicles over 7,000. The first convent established at Baco is later moved to Calapan. Convents are also established at Naojan, Calavite, and Mangárin (which is later removed to Bongabong, because of its unhealthy site and the raids of the Moros), all of which have their visitas. A mountain mission established later results in a great increase to the Christians of Mindoro. The succeeding chapter deals with the resumption of the Recollect missions in Calamianes which have been abandoned in 1662 because of the Chinese pirate Kuesing, and the consequent withdrawal of the support of the military. All but two of the missions, those in Cuyo and Agutaya, which are retained by the Recollects, have been given into the care of one secular priest, and this arrangement is maintained until 1680, when the Recollects (although somewhat unwillingly on their part) again accept the ministry of those islands. In November of 1680 three religious are sent there, the possession of the Recollects is given royal confirmation in 1682, and in 1684 the arrival of a new mission allows them to assign other workers to the field. There are plenty of hardships to suffer, but the fruit is great. New missions are established, and by 1715 the number of Christians has risen from 4,500 in 1680 to 18,600; and in 1735 Calamianes and Romblón contain 21,076 Christians. Certain missionaries are named and praised for their work. Incidentally an interesting description is given of the training of the native children for the service of the Church, by which our author refutes the charge that the religious have many servants.