Many Iroquois religious dances require that participants wear "Indian" costume. Here Nicholson Parker (c. 1820-1892) and Caroline Parker (c. 1830-1892) are shown in Iroquois dress in the mid-nineteenth century. While there is some variation in "Indian" dress in current Longhouse rituals, similar costume can still be seen at religious dances and rites which require that Indian dress be worn. The Parkers were brother and sister to Ely S. Parker, who supplied Lewis Henry Morgan with much of the data found in his pioneering study of the Iroquois. These plates illustrated Morgan's League of the Ho-dÄ-no-sau-nee [or] Iroquois (Rochester, 1851).