This Chapter deals with the ritual practice of adat which is nearly the same thing as what Rippin called the “additional ritual”, the ritual outside the enactment of the Five-pillars, used by the Muslims to express their identity. It thus, lies outside the domain of ibadat in the narrower sense. Some of the adat activities are undeniably Muslim creations, some others have unclear origins but all of these practices have an Islamic flavour. Other activities refer to indigenous ceremonies which are likely to have a non-Islamic origin but are tolerated or retained because they have been Islamised in that they have undergone modification from their original form. Their existence in their present form is harmless to the Islamic faith or has even been incorporated into it and is used as an expression of particular local Muslim identity. Among adat rituals belonging to the first type are commemorations of the Islamic holy days; those belonging to the second are thanksgivings (syukuran or tasyakuran) and slametan related to the individual life cycle and the commemoration of the death of a person. Examples of those belonging to the third are the communal feasts related to the agricultural season.