1824
Thiebault, a Frenchman, established himself at the Turtle village, probably about this year.
The propertyGrade A · 1 independent source
The evidence
“Others married among them and became what may be called Indian residents. Of the latter class was one Thiebault, a Frenchman, who established himself at the Turtle village probably about the year 1824. His cabin is noted in the plat of the Government survey of the township in 1834.”
1879-history-of-rock-county/08-rock-county-ch02-mounds-indians-black-hawk-settlement.md, PDF p. 320
Butterfield, C. W., et al. The History of Rock County, Wisconsin: its early settlement, growth, development, resources, etc. Chicago: Western Historical Company, 1879. Cornell University Library via the Internet Archive, archive.org/details/cu31924028871585.
Grade A: Found on a page of one of our sources