It is unclear how or when the tradition began. Many prayer ladies say they inherited their jobs from their mothers and grandmothers. Since they wear casual clothing with no identifying marks, it can be difficult to distinguish them from the regulars shuffling in to pray.Quiet and still, they wait like stone angels in the back of the 16th-century church. They sit not on the wooden pews reserved for worshipers but on plastic chairs they bring from home. Unlike the street vendors hawking candles, amulets and herbal cures in the crowded plaza outside, they are not allowed to approach churchgoers or advertise their trade.