Complex sentence: On September 28,1786, the residents of Kentucky County began petitioning the Virginia legislature for permission to become a "free and independent state, to be known by the name of the" Commonwealth "of Kentucky".
Split into simpler sentences: On September 28,1786, the residents of Kentucky County began petitioning the Commonwealth of Virginia legislature for statehood. They wished the County to be recognized as a "free and independent state, to be known by the name of the" Commonwealth "of Kentucky".