Many of the Amazonian peoples were grouped into small villages and presented a simple and egalitarian socio-political organization. In this context, some tribes remained very isolated, while others were constantly at war, either against rival groups from the same community or against neighboring tribes. Other peoples subsisted peacefully with each other, sometimes linked by commercial ties. Warfare occupied an important place in the social and religious life of various tribes. The chiefs obtained their prestige thanks to the capture of prisoners and the courage shown in combat. Among the more advanced peoples, such as the Tupi, political power was in the hands of a council of elders that met almost daily. The entire tribe had to obey the rules approved in that council, which effectively meant that any dissident could be accused by sorcerers as an evil spirit sentenced to death by the community. There were no major social ranks and no personal possessions. A communal attitude toward land and food predominated. The basic social unit was the family, generally self-sufficient, where the father was in charge of the daily sustenance (hunting, fishing, incipient agriculture) and the women cultivated and gathered fruits. In many towns matriarchy prevailed and the children belonged to the mother's social group. Ceremonies such as the covada reflect the role assigned to men in these matriarchal cultures. In other tribes polygamy was practiced, especially among chiefs and famous warriors.