My research shows that there is some difference of opinion concerning whether there were changes to the Cheyenne Sun Dance ritual between 1905 and present day. George Keithley in an essay called Summer Solstice which was published in 2012 claims that the Sun dance did change. Another article on the subject by George A. Dorsey written in 1905 claims that there is no evidence of such changes. When discussing my research I will use the 1905 source for discussing the framework of the Sun Dance ritual while using the 2012 source for discussing whether there were changes in the ritual after encountering Europeans.
According to George A. Dorsey the Sun Dance in most cases occurs at most once a year. There can be years where there is no Sun Dance ritual. The reason for this being that whether one occurs or not is due to whether someone takes the vow to put on the ritual. The vow is normally taken during a time of great need. For example when trying to escape an enemy, to save a family member, or personal protection. Per Dorsey the number of days over which the ritual takes place is not set and can vary depending upon how long a period of fasting is expected to last. Dorsey claims that there was no change in the Sun Dance ritual and that the different violent rituals that occurred during his observation of a Sun Dance also occurred at other times as well. However, According to George Keithley after encountering Europeans Native American’s had lost faith in the Sun Dance and the violence that occurred during the Sun Dance escalated after interaction with Europeans. Also Keithley states that more men volunteered for the violent portions of the ritual following European contact.
Keithley, George “Summer Solstice” Sewanee Review Vol. 120 Issue 2 (Spring 2012): 304 – 313
Dorsey, George A. “The Cheyenne. II. The Sun Dance” Publications of the field Columbian Museum. Anthropological Series Vol. 9, No. 2 (May 1905) 57 – 186
Anthropology of U.S. Society 