There were three brothers who went to Illinois. Most genealogists will tell you if it starts with "there were three brothers" or a descent from an Indian princess or royalty it is likely fantasy genealogy. Not so fast.
David Clark of Rahway, New Jersey, married Sarah Winans. They had nine known children, all born in New Jersey. The youngest three, all boys, were David, John Winans and Isaac - our three brothers who went to Illinois. They all went from Rahway to Miami County, Ohio, to Sangamon County, Illinois, although not together.
David Clark went to Kentucky in 1798 and married Rachel Rutter there about 1800. She died in 1804. He went to Cincinnati in 1805, made brick for the first brick house there, then went back to New Jersey where in 1806 he married Sarah Winans. They became, like his parents, David Clark and Sarah Winans. In 1809 they moved to Miami County, Ohio. David's oldest son Richard Winans Clark married John Winans' second daughter Margaret Ann Clark in 1829 in Miami County, Ohio. The same year David, Sarah, the newlyweds and most of David and Sarah's other children packed up and moved to Sangamon County, Illinois. David was a farmer and a Methodist preacher.
John Winans married Ann "Nancy" Isgrig in Bourbon County, Kentucky. They soon went to Miami County, Ohio. Family records indicate that their son Daniel was born in Ohio in 1812 but John Winans did service in the War of 1812 in the Kentucky Mounted Volunteer Militia, mustering in on August 31, 1813. After that he was undoubtedly in Ohio. He did not settle in Sangamon County, soon to be Logan County, Illinois, until 1838 when he was 60 years old. At that time his eldest daughter Hannah and her husband Asa French also moved to Logan County.
Isaac, the youngest, first married Lydia Zeliph. She died before 1821. He then married the widow Sarah Royal Stought, in Miami County, Ohio. In 1829 they went Illinois, almost certainly stopping first in Sangamon County, where Sarah's daughter Hannah by her first marriage married David Ward Clark, a child of Isaac's brother John Winans, in Sangamon now Logan in 1831. Note that John Winans was not yet in Illinois but several of his children were. Issac settled in Fulton County where he owned a water powered grist mill.
Three brothers did come to Illinois. So far no Indian princesses or royalty. My emigrant Isgrig ancestor was transported to America by his majesty, a prisoner from Old Bailey - does that make a royalty connection?