sentences:  In 1809, when Illinois became a separate territory, Territorial Secretary Nathaniel Pope, in his capacity as acting governor, issued a proclamation establishing Randolph as one of the Illinois' two original counties.The county's boundaries were last changed in 1827, when land was taken to form Perry County.The Mississippi River has played a prominent role in the county's history, altering its boundaries in 1881 when it severed the isthmus that connected Kaskaskia to the Illinois mainland, destroying the original village of Kaskaskia and forcing its historic cemetery to be relocated across the river to Fort Kaskaskia.