In indigenous Chagga cosmology, all human activities have potential spirit-worldly significance. Thus, the seen and the unseen worlds are closely linked. Dead ancestors care how their descendants behave. Living persons are capable of invoking God or the spirits for benign or malign purposes. Incurable illness, infertility, or other misfortunes are considered likely to have been caused by human or spirit agencies. Spells, curses, amulets, and witchcraft were (and are today) commonplace, both to defend and to harm. Diviners could (and can) be consulted. Rituals mark all life-cycle events. Christian ideas and rituals are closely intertwined with indigenous conceptions and ceremonies.