In the course of the centuries, in the liturgical Tradition the parts of the body of the sick person to be anointed with Holy Oil were more explicitly defined, in different ways, and there were added various formulas to accompany the anointings with prayer, which are contained in the liturgical books of various Churches. During the Middle Ages, in the Roman Church there prevailed the custom of anointing the sick on the five senses, using the formula: "Per istam Sanctam unctionem et suam piissimam misericordiam, indulgeat tibi Dominus quidquid deliquisti," adapted to each sense.
After the Council of Florence had described the essential elements of the Anointing of the Sick, the Council of Trent declared its divine institution and explained what is given in the Epistle of Saint James concerning the Sacred Anointing, especially with regard to the reality and effects of the sacrament: "This reality is in fact the grace of the Holy Spirit, whose anointing takes away sins, if any still remain to be taken away, and the remnants of sin; it also relieves and strengthens the soul of the sick person, arousing in him a great confidence in the divine mercy, whereby being thus sustained he more easily bears the trials and labors of his sickness, more easily resists the temptations of the devil 'lying in wait' (Gen. 3:15), and sometimes regains bodily health, if this is expedient for the health of the soul." The same Council also declared that in these words of the Apostle it is stated with sufficient clarity that "this anointing is to be administered to the sick, especially those who are in such a condition as to appear to have reached the end of their life, whence it is also called the sacrament of the dying." Finally, it declared that the priest is the proper minister of the sacrament.
The Second Vatican Council adds the following: "'Extreme Unction', which may also and more fittingly be called 'Anointing of the Sick,' is not a sacrament for those only who are at the point of death. Hence, as soon as any one of the faithful begins to be in danger of death from sickness or old age, the appropriate time for him to receive this sacrament has certainly already arrived." The fact that the use of this sacrament concerns the whole Church is shown by these words: "By the sacred anointing of the sick and the prayer of her priests, the whole Church commends those who are ill to the suffering and glorified Lord, asking that He may lighten their suffering and save them. She exhorts them, moreover, to contribute to the welfare of the whole People of God by associating themselves freely with the passion and death of Christ. All these elements had to be taken into consideration in revising the rite of Sacred Anointing, in order better to adapt to present-day conditions those elements which were subject to change. (Apostolic Constitution: The Sacrament of Anointing of the Sick, 30 November 1972).