The oldest legends of the Arapaho say that long ago they left the headwaters of the Mississippi and traveled to the Upper Missouri country where they made first contact with the Cheyenne who would remain their close friends and allies. In approximately 1835, many bands of the Arapaho and Cheyenne moved south into eastern Colorado, while a few bands of each tribe remained in Wyoming and Montana. This group would ally with the Sioux and become enrolled in the growing dissention and conflict that ultimately led to the joint defense of their homelands, a period now referred to as the Sioux Wars.