The war parties became larger and more general as the summer advanced, driving whites off the plains between the two trails for several hundred miles. But as fall approached, the tribes as usual sought peace. The Indians' time for war was summer. Without supplies, they were unable to fight through the winter, so that autumn brought them into a mood well disposed to peace, reservations, and government rations. Major Colley, the agent on the Sand Creek reserve at Fort Lyon, received an overture early in September. In a letter written for them on August 29, by a trader, Black Kettle, of the Cheyenne, and other chiefs declared their readiness to make a peace if all the tribes were included in it. As an olive branch, they offered to give up seven white prisoners. They admitted that five war parties, three Cheyenne and two Arapaho, were yet in the field. Upon receipt of Black Kettle's letter, Major E. W. Wynkoop, military commander at Fort Lyon, marched with 130 men to the Cheyenne camp at Bend of Timbers, some eighty miles northeast of Fort Lyons. Here he found "from six to eight hundred Indian warriors drawn up in line of battle and prepared to fight." He avoided fighting, demanded and received the prisoners, and held a council with the chiefs. Here he told them that he had no authority to conclude a peace, but offered to conduct a group of chiefs to Denver, for a conference with Governor Evans. On September 28, Governor Evans held a council with the Cheyenne and Arapaho chiefs brought in by Major Wynkoop; Black Kettle and White Antelope being the most important. Black Kettle opened the conference with an appeal to the governor in which he alluded to his delivery of the prisoners and Wynkoop's invitation to visit Denver. "We have come with our eyes shut, following his handful of men, like coming through the fire," Black Kettle went on. "All we ask is that we may have peace with the whites. We want to hold you by the hand. You are our father. We have been travelling through a cloud. The sky has been dark ever since the war began. These braves who are with me are all willing to do what I say. We want to take good tidings home to our people, that they may sleep in peace. I want you to give all these chiefs of the soldiers here to understand that we are for peace, and that we have made peace, that we may not be mistaken by them for enemies." To him Governor Evans responded that this submission was a long time coming, and that the nation had gone to war, refusing to listen to overtures of peace. This Black Kettle admitted.