The Iroquois or Five Nations comprised the Cayuga, Mohawk, Oneida, Onondaga and Seneca and resided in the central and western portions of present-day New York. Experts disagree about whether the Iroquois were indigenous to New York or if they came originally from the Mississippi Valley. In any event, they had developed a complex matrilineal civilization marked by a significant degree of democracy. They lived in bark-covered longhouses that were surrounded by stockade-like structures, and depended upon agriculture as the prime source of food. Around 1570, in an effort of limit warfare and to end cannibalism, the five tribes formed the Five Nations or Iroquois Confederacy. All tribes had to concur by vote for war, but there were occasional instances of warfare within the confederacy. The Five Nations developed into a remarkable power, especially after procuring firearms from the Dutch, and came to control a huge portion of eastern North America. The confederacy was enhanced in the mid-18th century by the addition of the Tuscarora, who had been forced out of North Carolina, and became the Six Nations. The Iroquois became the longtime ally of the British, most likely as a reaction against French incursions into their territory. Nevertheless, the French sponsored missionary activities among the Iroquois and were successful, around 1670, in persuading a segment of the Mohawk to leave the confederacy. These Catholic Mohawks joined the French in campaigns against the British.